October 13th, 2011

Repair Your Hard Disk in Single User Mode

Mac OS X has a built-in disk diagnostic and repair program called fsck or file system consistency check. Unlike Disk Utility, which can only verify the current startup disk, fsck will verify and repair the current startup disk. Here’s how to verify and repair your startup disk with fsck.

1. Start or restart your Mac. As soon as you hear the startup tone, press and hold Command-S on the keyboard. Keep holding down those keys until you see a black screen with white lettering. This is called “booting into Single User Mode.” As soon as you see the black screen with white lettering, you can release the keys.

Single User Mode WindowThe single user mode screen

As the Mac boots in this mode, the screen reports each step of the process. Wait until the scrolling white text stops. The last line should end in root#.

2. Right after the root# prompt, enter the following:

/sbin/fsck -fy

Press the Return key.

You’ll see the prompts in the picture above as each part of the hard drive’s directory is checked. (Checking extents overflow file, Checking catalog file, Checking multi-linked files, etc.) It will take a few minutes. At the end, if your drive was OK, the screen will say “The volume (name of your hard drive) appears to be OK”. If any repair was made, you’ll see the prompt, “FILE SYSTEM WAS MODIFIED”. Then, you’ll see the root# prompt again.

Right after the root# prompt, enter the following:

reboot

Press the Return key. Your Mac should restart normally.

152 Responses to “Repair Your Hard Disk in Single User Mode”

  1. Sanchit Says:

    April 2nd, 2013 at 6:11 am

    I got “The volume Macintosh HD could not be repaired.” message after this is complete?

    What should I do now? Please help.

  2. darryl Says:

    April 3rd, 2013 at 3:37 am

    There are a few possible next steps.

    1. Contact a Mac consultant to have your disk repaired. To find a Mac consultant that’s part of the Apple Consultant’s Network, go to http://consultants.apple.com and enter your zip code. A list of consultants in your area will appear, along with addresses, phone numbers, and star ratings from their clients.

    2. If you prefer to go the do-it-yourself route, purchase Disk Warrior or TechTool Pro. You can’t repair the disk from which your Mac is currently booted, so you’ll have to boot from a different drive, install Disk Warrior or TechTool Pro on that disk, and run it. Both those programs have much greater capabilities for repairing damaged disk directories than the FSCK routine built into Mac OS X.

    3. If you want to go the cheapest do-it-yourself route, simply back up your drive to another drive, reformat it with Disk Utility, then restore all the data from the backup. The downside of this choice is that if the disk’s directory is badly damaged, some files may not be able to be copied accurately…you may lose a some of your files. That’s less likely with the other two choices.

    Everything Macintosh is a Mac consulting company, and we can help if you contact us at 800-916-9695 or email us at . Our service rates are posted on the Rates & Terms page of this web site.

    Hope that helps.

  3. Sanchit Says:

    April 22nd, 2013 at 5:52 am

    Hey Darryl. Thanks a lot. I followed 3rd choice and fortunately got all of my data :)

  4. Darryl Says:

    April 22nd, 2013 at 6:50 am

    I love it when things work!

  5. Jeffrey Says:

    May 6th, 2013 at 6:17 pm

    Thank you! Worked perfect.

  6. Lee Says:

    May 30th, 2013 at 6:11 pm

    Hi Darryl I’ve tried /sbin/fsck -fy. And I get this message

    The volume macintosh hd could not be verified completely. Please help I’m dying here

  7. darryl Says:

    May 30th, 2013 at 6:55 pm

    Sorry to hear you’re having a problem, Lee. If repairing the disk in single user mode fails, it means one of two things. Either your hard drive itself is failing (a hardware failure), or the directory damage on your hard drive is beyond the capability of the built-in repair procedures in OS X.

    The primary goal this situation is to prevent the loss of your files, so here are the steps I take in cases like this.

    1. Before doing anything else, it’s important to attempt to make a backup of the failed drive. If the backup is successful, you’ll know you have your documents, pictures, music…whatever you keep on the computer.

    2. Purchase a copy of Disk Warrior. Disk Warrior is a commercial disk repair program that comes on a bootable DVD, and it’s directory repair capabilities are much more comprehensive than the built-in routines in OS X. Disk Warrior will analyze the current state of your hard drive and create a completely new, optimized directory. Once that’s done, if the Disk Warrior finds the hard drive itself to be healthy, it can write the optimized directory on your hard disk, replacing the damaged directory. In many cases, that will fix the problem and you’ll be able to reboot from your internal drive. If Disk Warrior finds your hard disk is not healthy (it has hardware issues, or has insufficient space to write the new directory), it will let you know…and won’t be able to write the replacement directory. However it will be able to mount an image of your damaged drive using the new directory on screen, and you can back up all your files from that image either using a backup program like Carbon Copy Cloner or SuperDuper!, or manually drag the files to another drive.

    3. If all of the above fails, and Disk Warrior reports that the drive has hardware problems that make it impossible to create the optimized directory or display the image of your disk on screen, you’ll have to send your drive to a commercial data recovery company. Data recovery companies are capable of disassembling your hard drive in clean room conditions, and either repairing the drive itself or removing the actual disk within the drive that contains the data and implanting it in another working mechanism, then recovering the files. The hardware issues that typically affect drives are that the motor responsible for spinning the disk is no longer able to make it spin at the correct speed (or at all), the read/write heads in the drive have become damaged and can no longer read the magnetic charges on the disk’s surface, or damage has been done to the disk’s surface.

    I see your email address is at hotmail.co.uk. I can certainly recommend data recovery companies I’ve had good results with, but since we’re based in the US you’d probably do better to google data recovery companies in the UK. Let me know how I can help further. If I were closer to you I’d come by and have a look…under the circumstances it would be a very long commute.

  8. jordan Says:

    July 12th, 2013 at 7:22 pm

    will this work for a corrupted hd i want to wipe my mac entirely

  9. darryl Says:

    July 13th, 2013 at 12:17 am

    It may work to repair the damage on your corrupted HD, but it won’t wipe your Mac completely. If you’re really serious about completely wiping your hard disk, here’s what to do:

    If you’re running OS X 10.7 or later, reboot your computer while holding down the Option key. The initial gray screen will show icons for your normal hard drive and a Recovery Partition. Click on the Recover Partition and boot up. Once you get to the desktop, a box will appear that gives you several options. Click the option to launch Disk Utility. In the Disk Utility window, click on your hard drive’s name in the column at the left side. In the main portion of the window, click the Erase button. In the Erase window, click on the Security button, and click the option to zero all sectors, then click the OK button. Now click the Erase button to erase the hard disk. Clicking the zero all sectors option not only writes zeros over all your data, it also checks the entire disk surface for unreliable sectors. If it finds any, it adds those sector numbers to a list of “do not use” sectors, after which the drive will not write any data to those sectors…making the entire drive more reliable.

    If you’re running OS X 10.6 or earlier, you’d have to boot your Mac from an installation DVD or an external hard drive, launch Disk Utility from that drive, and do the same thing. OS X 10.6 and earlier don’t have a Recovery Partition.

    Hope that helps.

  10. Honey Says:

    July 25th, 2013 at 1:32 pm

    I got the message that my drive seems to be okay, yet the reboot sends me again to endless gray screen.

  11. darryl Says:

    July 26th, 2013 at 12:58 am

    Next try a “Safe Boot”. The Safe Boot disables any third party software that normally loads at boot up, but more importantly it rebuilds the Launch Database on your hard disk. Rebuilding the Launch Database frequently resolves the problem of the gray screen.

    Turn off the Mac. Then start it up while holding down the Shift key. (If you have a wireless keyboard, begin holding down the Shift key after you’ve heard the startup chime.) Continue to hold down the Shift key until you see a status bar at the bottom of the screen, beneath the gray Apple and the spinning gear. Then release the key.

    Your Mac will always boot to the login screen when doing a Safe Boot, even if it normally goes directly to the desktop. Once you get to the login screen, simply restart one more time, this time without holding down any keys.

    Good luck!

  12. Edwin Says:

    August 8th, 2013 at 12:46 pm

    After following this, in the end I get the

    “volume could not be repaird after 3 attempts”
    “Disk has been modified”

    Or at least close to that.

    Any suggestion on this?

  13. darryl Says:

    August 8th, 2013 at 1:03 pm

    That means that the disk’s directory is damaged beyond the ability of the built-in repair capabilities of OS X. It’s at this point I usually recommend getting a Mac professional like Everything Macintosh involved. All of us carry disk repair programs with capabilities far beyond those built into OS X. However if you want to continue to try to fix this yourself, there are commercially available disk repair utilities that do a great job. My favorite is Disk Warrior from Alsoft (http://www.alsoft.com/diskwarrior/). It’s easy to use and completely rebuilds an optimized disk directory for your drive, and costs roughly $100. If that fails, your drive likely need to be recovered rather than fixed, and at that point you really need to get a Mac professional like Everything Macintosh involved.

  14. Edwin Says:

    August 9th, 2013 at 7:35 am

    Thanks. Since being in The Netherlands, I think I will go to Macrepair.nl or one of the other repair sites.

    Not much luck with Apple this year :(

  15. Brendan Says:

    September 15th, 2013 at 10:00 pm

    I followed the prompts, got “FIle System was Modified,” but then when I tried to reboot, I got a kernel panic. Any ideas?

  16. darryl Says:

    September 16th, 2013 at 2:18 am

    Did you see the gray apple, then get the kernel panic? If that’s the case, either there is a problem with your OS X installation, there is a problem with the launch databases on your hard disk, or there is a third party piece of software loading at startup that’s triggering OS X to panic.

    To figure out which, try Safe Booting…start your computer, and as soon as you hear the startup chime begin holding down the Shift key on the keyboard. That does two things: it disables third party software from loading, and it rebuilds the launch databases on your hard disk. Both of those things are beneficial. A safe boot takes longer than a normal boot because of the rebuilding of those databases, so keep holding down the Shift key until you see a status bar appear at the bottom of the screen (OS X 10.6-10.8), or until you get to the login window (OS X 10.4 & 10.5).

    Just so you’re not surprised, even if you normally boot directly to your desktop, when you safe boot you always go to the login window…you have to enter your password to get to your desktop.

    If you get a kernel panic during the safe boot (and never get to the login window), it’s a reasonably safe bet that there’s a problem with OS X itself, so you should reinstall it.

    If you get to the login window, log in by entering you password. When you get to the desktop, simply restart normally without holding down any keys.

    If you now boot up normally, the problem was likely with the launch databases, and the safe boot resolved it by rebuilding them.

    If you still get the kernel panic, there’s probably some third party software trying to load during boot up, and it’s causing the panic either because it’s corrupt or incompatible with the version of OS X you’re running. In that case you’d have to safe boot so you can boot up, then disable any third party software normally loads at startup. Enable each piece of third party software one-by-one, rebooting after each one is enabled to see whether the newly enabled piece of software causes the panic. When you find the culprit, if this is software you really need, check to see if there’s a later version available and install it.

    If you need further help you can contact us for remote, phone, or email support. Hope this fixes things, though.

  17. Kayla Says:

    September 19th, 2013 at 2:07 pm

    I completed each step as suggested above. When it came time to reboot it went to the gray apple screen with the loading wheel. My computer continues to stay on this screen without any progress. Do you have any other suggestions?

  18. darryl Says:

    September 19th, 2013 at 7:13 pm

    Funny…you’re the second person to ask this question recently. For my answer, look at this reply I gave to Brendan on September 16:

    http://www.everythingmacintosh.com/tech-notes/repair-your-hard-disk-in-single-user-mode/#comment-5648

  19. Misty Says:

    October 23rd, 2013 at 1:20 am

    I was able to log in single user mode. I did fsck -fy 3 times until it said the disk was ok. I was able to navigate and see my files still there. I then tried to reboot and still went to just the gray screen. So now I’m trying to boot into safe mode. I get the progress bar, apple and spinning cog. Then it just goes to a blue screen. I never do hear the startup chime. No idea what to do now.

  20. darryl Says:

    October 23rd, 2013 at 4:37 am

    The next step is to try a Safe Boot. Begin with your Mac turned off. Start up your Mac, and immediately after you hear the startup tone begin holding down the Shift key on the keyboard. (If you have a wired keyboard, or are using the built-in keyboard on a laptop, you can start holding down the Shift key even before you startup…but with wireless keyboards it’s important to wait until you hear the startup tone because the Bluetooth connection between the computer and keyboard doesn’t happen until after the startup tone.)

    The bootup will take longer than usual because the Safe Boot does two things. First, it disables any third party software that normally loads at startup. Second, and more importantly in this case, it rebuilds critical databases on your boot hard drive called Launch Databases. Corruption in these can cause the boot and blue screen issues you’ve described.

    Keep holding down the Shift key until you see a status bar appear on screen below the gray apple and spinning gear. Once you see the status bar, release the Shift key. (If you’re running a version of OS X earlier than 10.6, there is no status bar…just keep holding down the Shift key until you get to the login screen.)

    Even if your Mac normally boots directly to the desktop, when you Safe Boot it will go to the login screen. Enter your password, and go to the desktop. Then simply reboot normally.

    Let me know if that resolves the issue!

  21. Yousef Says:

    November 9th, 2013 at 7:59 am

    Hey it’s says the volume Macintosh had appears to be ok what should I do I reboot it but it’s still blue screen

  22. darryl Says:

    November 18th, 2013 at 2:57 pm

    The next step is to do a “Safe Boot” Goldy. Start with your Mac powered off. Press the power button, and when you hear the startup sound hold down the Shift key on your keyboard. Continue to hold the shift key until you see the gray screen with the dark gray apple, and, at the bottom of the screen, a status bar. As soon as you see the status bar you can release the Shift key. Booting up will take longer than usual because the Safe Boot rebuilds the Launch Database, an important file on your hard drive. When that file becomes damaged (occasionally), it can prevent booting up.

    If that fails to resolve the issue, we’d probably need to see your Mac to make a diagnosis. Let us know if we can be of further help.

  23. tim Says:

    December 11th, 2013 at 1:53 am

    Doing a forced FSCK saved me.

    I had to run it twice as it will only do 3 passes by default (after the first set of passes, it said it couldn’t fix the disk, but a subsequent run got everything).

    Loginto to single user mode then:

    fsck_hfs -y -Rc -d /dev/disk0s2

    GOLD! Saved my bacon. Hope it saves yours too.

    *** I have no idea why OSX just doesn’t do a forced FSCK in the first place. Stupid.

  24. darryl Says:

    December 11th, 2013 at 2:25 am

    Bravo!!

  25. Roger Says:

    December 11th, 2013 at 1:48 pm

    My Macbook with Mountain Lion will not boot either. I tried your suggestion of Command+S and /sbin/fsck -fy Came back modifications were made. i ran it again and got Disk appears to be ok. Rebooted and the first time it did boot successfully but then locked up. Did those steps again and each time got Disk appears to be OK. But it gets hung up at the gray apple logo screen with the fan spinning fast. This drive is a 1Tb drive I added after my first driver failed. I am wondering if I need to try Disk Warrior?
    Any suggestions would be most helpful! Thanks.

  26. darryl Says:

    December 11th, 2013 at 5:04 pm

    The next step is to try a “Safe Boot”. The Safe Boot disables any third party software that normally loads at boot up, but more importantly it rebuilds the Launch Database on your hard disk. Rebuilding the Launch Database frequently resolves the problem of getting stuck at the gray screen with the Apple. A corrupt launch database can cause boot up problems and lots of other oddball issues where programs don’t launch or behave strangely.

    Turn off the Mac. Then start it up while holding down the Shift key. (If you have a wireless keyboard, begin holding down the Shift key after you’ve heard the startup chime.) Continue to hold down the Shift key until you see a status bar at the bottom of the screen, beneath the gray Apple and the spinning gear. Then release the key.

    Your Mac will always boot to the login screen when doing a Safe Boot, even if it normally goes directly to the desktop. Once you get to the login screen, simply restart one more time, this time without holding down any keys.

    Let me know if that fixes things.

  27. Roger Says:

    December 11th, 2013 at 6:22 pm

    OK, so I do that and get the status bar, it goes through that step but hangs when the status bar goes away and the spinning gear starts. It spins for about 30 seconds then stops and thats as far as it goes….

  28. David Says:

    December 16th, 2013 at 12:56 pm

    My computer shuts off before booting into the OS. Tried running fsck and got this…can anyone make sense of it? Also, is there any way to restore the OS (formatted for all I care) without a disc..and will that fix the problem?

    Here’s the message I got;

    /dev/rdisk0s2
    Root file system
    Executing fsck_hfs (version diskdev_cmds-491 .6~3).
    Checking Journaled HFS Plus volume.
    Checking extents overflow file.
    Checking catalog file.
    Invalid sibling link
    (4, 7543)
    Rebuilding catalog B-tree.
    Disk full error
    The volume Macintosh HD could not be repaired.
    /dev/rdisk0s2 (hfs) EXITED WITH SIGNAL 8

    Anyone who can help is a friggin’ saint!

  29. darryl Says:

    December 16th, 2013 at 2:57 pm

    In the message you got, third line from the bottom, it says “Disk full error”. Your disk doesn’t have enough free space for fsck to do its job. Computers use free space on the hard disk as temporary work space, and when there isn’t enough free space available they can’t do their job. Lack of free space is also one reason a computer runs very slowly.

    You either need to replace your internal drive with a larger one (using a disk copying program like Carbon Copy Cloner or SuperDuper! to copy all the data from your existing drive to the new one)…which would give you more free space on the internal drive…or copy some of the data on the internal drive to another drive, then trash it from the internal and empty the trash to reclaim the space.

  30. David Says:

    December 17th, 2013 at 4:33 am

    Is there any way I can delete some files from single user mode?

  31. David Says:

    December 17th, 2013 at 4:58 am

    I was able to delete my downloads folder which allowed an fsck to run! I’ll check back in soon.

  32. jude Says:

    December 19th, 2013 at 3:03 pm

    when I use a single user mode the checks everything out as good buT, as I try to boot into my primary HD the message kernel message sex is too large now I’m trying tochange the volume size or delete its all together or make mine PC recognize it nothing is working help

  33. Matt Says:

    December 20th, 2013 at 7:02 pm

    Upgraded to mavericks nothing but pain. Followed advice above. Keep getting incorrect number of thread records. 4,228

  34. darryl Says:

    December 20th, 2013 at 9:08 pm

    I’ve been recommending to my clients that they wait a while to upgrade to Mavericks. Typically, the initial release or two of any software has issues. These days, the problem seems to be that most of the “beta testers” Apple uses are their third party developers…most of whom don’t use their computers the way most people do. They find the technical bugs well enough, but not the usability bugs. Once the new release becomes available to everyone, the earliest adapters become the guinea pigs that get bit by the usability bugs. They’re always corrected in subsequent updates, to I always recommend waiting about 3-6 months before upgrading to a new major version of any software. That gives plenty of time for the developer to release several updates to correct issues, and in the case of OS X gives the third party developers enough time to develop stable updates for their programs to run under the new OS. Sorry you had the problem.

    You’ll need to use a third party utility like Disk Warrior or TechTool Pro to fix your disk if using fsck didn’t work. I usually consider fsck, which uses the same disk repair routines as Disk Utility, as the most basic of the disk repair utilities, and also the one least likely to result in any unexpected data loss after the repair is complete. Disk Warrior is much more comprehensive, and not only repairs many more directory issues than fsck, but also creates a brand new, optimized directory for the hard disk that should run more efficiently than the older, fragmented directory. TechTool Pro is my third choice, and checks and repairs some issues than neither fsck or DiskWarrior do. So for most people (not techies like me), Disk Warrior’s simple interface and comprehensive repair capabilities make it the disk repair utility I strongly recommend in these cases. It’s about $99.99, and comes on a bootable DVD. Booting from the DVD allows Disk Utility to make its repairs on your boot disk.

  35. darryl Says:

    December 20th, 2013 at 9:10 pm

    If you’re running OS X 10.7 or later, my suggestion would be to boot from the recovery partition and reinstall OS X. (To do that, restart your Mac while holding down the Option key. A gray screen will appear with icons for all the bootable disks available to your Mac. Under OS X 10.7 or later, one of those is the Recovery Disk. Either double-click on it, or use the cursor keys on your keyboard to highlight it, then click the Return key to boot from it). You can find more info about reinstalling your OS in Apple’s tech notes…just search for “reinstall os x”.

  36. Steve Says:

    December 23rd, 2013 at 12:31 am

    i have completed everything that you said above. With recovery, normal or safe mode no matter what i use, my computer sits in the grey screen, with an apple logo, and the spinning circle, but then it freezes and then restarts automatically. not sure how to get osx to reinstall. I’ve used a fire wire to save my photos to another computer, now i just want to wipe it and get it working again. I’ve even made a bootable usb, but same problems, the computer freezes and then restarts

  37. darryl Says:

    December 23rd, 2013 at 6:29 pm

    If you’re running OS X 10.7 or later, reboot your Mac while holding down the Option key. Release the Option key when you get to a gray screen with icons for all bootable disks currently available to your Mac. One of those disks (normally located right next to the normal Macintosh HD icon) is the Recovery Disk. Either double-click on the Recovery Disk to boot your Mac from that disk, or use the cursor keys on the keyboard to highlight that icon, then press the Return key to boot from that disk. In the window that appears, you’ll see choices for reinstalling OS X, launching Disk Utility and other maintenance choices.

    If you’re running Snow Leopard or earlier, you must have an installer DVD to reinstall…

  38. Lynne Says:

    December 28th, 2013 at 5:13 pm

    Thanks a bunch! That worked :-)

  39. Lauren Says:

    January 4th, 2014 at 12:52 am

    Hello, thanks for all the tips. I have tried to get past the gray spinning screen numerous ways – reset pram, start in safe mode, etc., now I’m onto the single user mode, when it checks the extended attributes file it gives me this:
    Invaild index key (8, 499)
    It tries to repair then reaches and continues this process over and over…what should I do?
    I live overseas now so I don’t have my discs.
    Please help! Thanks.

  40. darryl Says:

    January 4th, 2014 at 1:25 am

    Normally, my next recommendation would be to repair your hard disk with a third party utility like Disk Warrior or TechTool Pro. Both come on bootable DVDs, so you’d boot from the DVD, then run the program on your internal drive. Unfortunately you’d have to buy those, so there’s another less costly step you can try first. If I were in your situation I’d so this:

    1. Clone (make an exact copy of) your entire startup drive to another hard drive. You can do this using Carbon Copy Cloner (which is my favorite backup/disk cloning program). Download it at http://www.bombich.com. There is a free trial, so you don’t have to buy it to use it once or twice. (Unfortunately, if you don’t have an external drive, you’ll probably have to buy one…but they’re usually not terribly costly.)

    2. Reboot up from the backup. (Use the Startup Disk preference pane to set the external backup disk as the boot disk, then restart).

    3. Use Disk Utility from the backup disk to erase your entire internal drive. Before clicking the Erase button, click the Security Options… button and click the choice to Zero all Sectors. You don’t need to use the options for writing zeros 7 times or more…once is enough.

    The reason for choosing this option has nothing to do with zeroing the data for security reasons…when you select this option, Disk Utility also checks every sector (data storage compartment) on the drive to make sure it’s reliably storing what’s written to it. Occasionally disks have sectors where the magnetic coating that stores the data is too thin to store the data reliably…and disks can develop more with use as they age. All disks also are designed with “spare sectors” that Disk Utility and other repair programs can substitute for unreliable sectors. That’s what we’re trying to do. Writing zeros and checking the disk for bad sectors makes this kind of erasure take much longer than normal…but it’s well worth the wait.

    4. Use Carbon Copy Cloner from the backup drive to clone the backup drive back to your internal drive, making it essentially the same as it was before…except healthy.

    5. Boot from the internal drive.

    If that fails, there may be no choice but to reinstall OS X.

  41. Isabella Says:

    January 5th, 2014 at 3:36 am

    I’ve done the safety boot and held it till the grey scale is there the I release, but its been on the grey page for At least an hr. What should I do?

  42. darryl Says:

    January 10th, 2014 at 3:30 am

    Here’s the reply I posted on July 26 for someone else who had the same experience, Isabella:

    Next try a “Safe Boot”. The Safe Boot disables any third party software that normally loads at boot up, but more importantly it rebuilds the Launch Database on your hard disk. Rebuilding the Launch Database frequently resolves the problem of the gray screen.

    Turn off the Mac. Then start it up while holding down the Shift key. (If you have a wireless keyboard, begin holding down the Shift key after you’ve heard the startup chime.) Continue to hold down the Shift key until you see a status bar at the bottom of the screen, beneath the gray Apple and the spinning gear. Then release the key.

    Your Mac will always boot to the login screen when doing a Safe Boot, even if it normally goes directly to the desktop. Once you get to the login screen, simply restart one more time, this time without holding down any keys.

    Good luck!

  43. Jacob Paterson Says:

    January 12th, 2014 at 12:17 pm

    Hi Darryl, I tried the command + S on bootup. I waited a few minutes and then a sprawl of errors came up. The error returned was cannot mount root errno = 19. I also went into Command + R and check Disk Utility, Machintosh HD is not even there. Could this be a mounting issue?

    Thanks, Jacob.

  44. Dee Goree Says:

    January 13th, 2014 at 2:17 pm

    Daryl, I’ve tried the CMD+S key and got the disk could not be verified. I have Bootcamp and my laptop won’t boot into Safe Mode, it goes directly to the Windows Prompt.

    I wasn’t able to reinstall Lion because the option was locked, no idea how to unlock it. Disk Utility says to back everything up and reformat the drive, how do I do that if I can’t get into my system to do that?

    I know this is a dumb question, but is there a way to run Disk Warrior without being able to actually get into you computer to run it?

  45. darryl Says:

    January 13th, 2014 at 7:35 pm

    Whether your internal drive is bootable or not, you’d need to run Disk Warrior from an external bootable drive (USB or a bootable CD, DVD, or Flash Drive). The reason is that Disk Warrior can’t repair the directory of the current boot drive. By booting from an external disk with OS X installed, the internal drive is no longer the current boot drive…and Disk Warrior can fix it. If you happen to have a friend or colleague with a Mac who can install OS X on an external USB hard drive, you can boot from that drive, copy Disk Warrior onto the drive, and run it on the internal drive.

  46. darryl Says:

    January 13th, 2014 at 7:39 pm

    The next step is a third party disk repair program like Disk Warrior or TechTool Pro. Both must be run from an external drive, because it’s not possible to repair the directory on the current boot disk your computer is using. If you have a backup drive that’s bootable, you could use that. Unfortunately Time Machine backups aren’t bootable. Another possibility would be to get a friend who has a working Mac to install OS X on an external USB hard drive. You could then use that drive to boot your Mac, copy on Disk Warrior or TechTool Pro, and repair your internal drive. Good luck!!

  47. bandatatman Says:

    January 15th, 2014 at 7:14 am

    Hey Darryl I rebooted into (command s) mode and entered the fsck_hfs -y -Rc -d/dev/disk0s2. I get b size = size of physical blocks
    B path =
    c size =
    E =
    d =
    f=
    (Etc etc….) what do from here

  48. Fiesta Says:

    January 17th, 2014 at 8:15 pm

    Even when i start from safe mode i still get a blue screen…

  49. darryl Says:

    January 17th, 2014 at 8:29 pm

    If you’re using a wireless keyboard, that can happen if you begin holding down the Shift key too soon. Wireless keyboards depend on software to load during the boot process before the computer recognizes the existence of the keyboard. If you press the Shift key before that happens, the computer doesn’t sense the actual pressing of the key. Try it again, and wait a second after you hear the startup sound before pressing the Shift key. Most 3rd party wireless keyboard have LEDs on them that display when the caps lock is on, and with those keyboards you can usually tell exactly when the computer has recognized them because that LED will blink. Apple’s wireless keyboards don’t have an LED, so it’s harder to tell when the computer recognizes them. But try a few different timings after the startup sound and you should eventually catch it at the right moment.

  50. darryl Says:

    January 17th, 2014 at 8:31 pm

    What you did was to get info on the disk rather than to initiate a directory scan and repair. Just type:

    /sbin/fsck -fy

    Then press the Return key.

    In a second or two, the directory scan will begin and you can follow the instructions in this article.

  51. fratres Says:

    January 23rd, 2014 at 10:53 am

    Hi darryl,
    thank you for your detailed description of the capabilities of single user mode.
    I have a corrupted system (or hard disk) and would like to check if I can repair it, but I have the following combination of errors:
    – full disk error when trying fsck -fy (only 300 MB left) and the cannot be repaired sentence
    – read-only of the root disk so I can’t delete files via target disk mode

    How can I enable the rights to wright on the disk, either in single user mode or via target disk mode?

    Any help is appreciated!

  52. Jim Says:

    January 24th, 2014 at 2:13 pm

    I am having problems similar to all those listed above.. When I try to boot normally, I get the grey screen with apple logo and loading bar.. The bar does not progress, I hear some computer-esque noises and it shuts off. The machine won’t boot in safe mode either.. Same thing happens. When I tried to boot to a recovery disk, nothing but OSX 10.9 was available… I clicked the arrow below that disk and the same thing happened. (Greg screen then auto shut-off.) I tried to do the FSCK process someone mentioned above and after it “checked the Catalog File” it said my OSX 10.9 could not be verified and the machine shut off.

  53. Spiros Says:

    January 25th, 2014 at 12:43 am

    Hi Darryl
    I have a MBP late 2011 with 2 disks. SSD and HDD
    I had the home folder on the HDD and bootet from the SSD.
    I recently got a larger SSD and there is no need to have the home folder at the HDD so I did a clean install, copied the files from the HDD to the SSD except the movies, iTunes, and iphoto folders which I will keep on the HDD since they are huge

    The problem is that iTunes wont see the library from the hdd since I get a “You don’t have permissions or the disk ids locked” message. I have changed the permissions from Get Info and applied to the containing folders. Iphoto has a permitions repair tool that fixes the issue and I see my previous library. I can;t even create the invisible link for the movies folder since i get a message on the terminal that the folder does not exist while it does.

    The remove ownership from disk check button doesn’t work as well

    Do you know how can I clear the permit ions for real from the HDD?

  54. darryl Says:

    January 26th, 2014 at 9:33 pm

    Insufficient space on the disk is a big problem. Any repair procedure requires free space on the hard drive to hold temporary files needed by the procedure if there isn’t enough RAM to hold them exclusively in RAM. Obviously 300MB isn’t sufficient in your case…which means you somehow need to boot from a different hard drive to repair this one. Here’s what I would try next.

    If you’re running OS X 10.7 or later, you can start up your Mac while holding down the Option key on the keyboard. You should come to a gray screen with icons for all drives available to your Mac which have a bootable OS X. With OS X 10.7 or later, there is an “invisible” Recovery Drive that will be listed in addition to your regular internal drive (Macintosh HD or whatever you’ve named it). Use the cursor or arrow keys on the keyboard to select the Recovery Drive. Your Mac will boot up to a screen that can run Disk Utility, reinstall OS X, and do other maintenance procedures. Plug in an external USB drive and install OS X on that drive…which will make it a bootable drive. Then boot up from that drive, move a few gigabytes of data from the internal drive to that external, then use Disk Utility (on the external drive) to repair the internal.

    Unfortunately if you’re running OS X 10.6.8 or earlier, there is no Recovery Drive…OS X must be installed from an external DVD. If you have that System Install DVD, you can boot from it and install OS X on the external USB drive…then do what I suggested after booting from the external drive. If you don’t have the System install DVD you’ll either need to get hold of one, or contact a local Mac service person to help you. Good luck!!

  55. darryl Says:

    January 26th, 2014 at 9:40 pm

    Unfortunately, Jim, your drive has more damage than the fsck procedure can fix. You’ll need to use a third party utility like Disk Warrior or TechTool Pro to fix your disk. Both are much more comprehensive than the basic repair procedures built into OS X itself. You’ll have to boot from the Disk Warrior or TechTool Pro DVD, then run the program to repair your hard disk. Disk Warrior is the easier of the two programs to use, is available for $99.95 from aloft.com, and has a great feature which brings up a preview of the repaired hard drive as an icon on your desktop before you actually tell it to do the repair. That’s handy if Disk Warrior can’t repair your disk (which can happen if there is insufficient free space for Disk Warrior’s temporary files)…you can recover the damaged drive by copying its entire contents from the preview image to an external drive, then erase or replace the internal drive and copy all your data back. Wish I had better news…

  56. darryl Says:

    January 26th, 2014 at 9:48 pm

    My favorite tool for fixing difficult permissions issues is BatchMod, available for free at http://www.lagentesoft.com/batchmod/index.html?utm_source=thedjlist.com&utm_medium=thedjlist.com_link&utm_content=dj_profile_link&utm_campaign=APPLICATIONS. BatchMod has settings that will unlock locked disks, change permissions on disks, folders, or files, clear xattrs, which are special settings OS X uses to identify its special folders (the ones that have special icons), clears Access Control List permissions (which sometimes get inadvertently added), and can apply the settings you set for a disk or folder to all the items within that disk or folder in a single procedure. Drag the HDD on top of the BatchMod icon, which opens its window, the make sure the boxes for Owner, Group, and Everyone all have X marks (not dashes or blank), then click the Clear ACLs (10.5+) box, click the Apply to enclosed box, then click the Apply button. That should give iTunes permission to see your iTunes music on that drive. Good luck!

  57. fratres Says:

    January 28th, 2014 at 3:30 pm

    Thanks for your reply, darryl. But your suggestion

    “Then boot up from that drive, move a few gigabytes of data from the internal drive to that external, then use Disk Utility (on the external drive) to repair the internal.”

    is exactly the problem I am having. Getting access to the internal drive is not my problem, I can use target disk mode from another mac or an installation disc (it’s 10.6.8), so I could copy all the stuff from the internal drive. But I don’t have write access to the drive so I can’t “move a few gigabytes” to get more space.

    Any solution for this?

  58. darryl Says:

    January 28th, 2014 at 8:43 pm

    If you’re unable to change the permissions for your drive in the Get Info box, the solution would be to log in as the “root” user. OS X treats the System as though it were another user…but a super user with unlimited access to everything…which overrides permissions issues. The short name for System is root.

    On OS X client versions, you have to manually enable the root user before you can log in as root. On OS X Server the root is enabled by default. In both cases, the root user defaults to using the same password as the original administrative user account on that computer, but you can enter a password at the time yo enable the root user as well.

    Instructions for enabling the root user are at this web page: http://support.apple.com/kb/ht1528

    Once you’ve enabled the root user on the computer to which you’ve connected the target disk computer, log out of the current account and log in with the user name root, and the password for the root account. Once you get to the desktop, you should be able to freely drag files and folders from the target disk drive.

    I that doesn’t resolve the problem, your target disk hard drive may need to be recovered.

  59. Walter Says:

    January 28th, 2014 at 10:49 pm

    Hi all,
    After install for working The CUDA SDK 5.0, i have reboot mavericks 10.9.1 and it freeze during boot.
    I have tryed safe mode but not working.
    I have tryed recovery mode, the disk get me The errors:

    Sibling link
    Could not repair disk

    With fsck_HFS i get : disk full error

    How can resolve first buy disk warrior, if it resolve The problem?
    I can buy with 100$ also a SSD disk if need change it.

    I have tryed to read disk with another mac and The users files are ok.

    Thanks.

  60. darryl Says:

    January 29th, 2014 at 5:23 am

    Hi, Walter. If you’re getting a Disk Full error, there isn’t enough available space on the hard disk for the temporary files created during fsck, or for the files created when the Launch Databases are recreated during a Safe Boot. (Either there really isn’t enough space on the drive, or the directory of the drive is damaged, so its reporting insufficient space even if there is available space.)

    The chances are that if the drive really hasn’t enough available space, Disk Warrior will also have a problem fixing it. Since you’re able to see all the files when you read the problem disk on another Mac, here’s another way to go about fixing the problem.

    1. Mount the problem disk on the other Mac and use a backup program like Carbon Copy Cloner or SuperDuper! (there are lots of them) to copy the entire problem hard drive to an external drive.

    2. Use Disk Utility to erase the problem drive. I recommend selecting Security Options… in the Disk Utility window and setting the slider to write a single pass of zeros over the entire disk. It’s not that I’m concerned about zeroing out the data. When you use that option, Disk Utility also checks the disk for sectors that don’t hold data reliably (because their magnetic coating is too thin). Whenever it finds sectors like that, it marks them as “do not use”. The drive has a certain number of “spare sectors” that can be substituted for bad sectors, so as long as the drive has spare sectors available, Disk Utility will substitute them if necessary. That way once the drive is successfully erased, you know it should be reliable.

    3. Us the backup program to restore the disk from the backup. Or, even better, install a clean copy of OS X on the disk, then use Migration Assistant to copy the programs and user accounts from the backup. By installing the clean OS X you know that the operating system is 100% healthy.

    Hope that helps!

  61. Walter Says:

    January 29th, 2014 at 11:53 am

    Hi, thx for reply,

    I have mounted the disk with Snow Leopard Server and I have copied only users folder, I need only this.

    I have recheck the disk with fsck_hfs, this is result:

    antwal-server:~ antwal$ fsck_hfs -fd /dev/disk5s2
    ** /dev/rdisk5s2
    Using cacheBlockSize=32K cacheTotalBlock=32768 cacheSize=1048576K.
    Executing fsck_hfs (version diskdev_cmds-491.6~3).
    Journal replayed successfully or journal was empty
    ** Checking Journaled HFS Plus volume.
    ** Checking extents overflow file.
    ** Checking catalog file.
    Invalid sibling link
    (4, 25339)
    ** Rebuilding catalog B-tree.
    BlockFindAll: found 263922 blocks but needed 346112
    Disk full error
    ** The volume Macintosh HD could not be repaired.
    volume type is pure HFS+
    primary MDB is at block 0 0x00
    alternate MDB is at block 0 0x00
    primary VHB is at block 2 0x02
    alternate VHB is at block 485320878 0x1ced68ae
    sector size = 512 0x200
    VolumeObject flags = 0x07
    total sectors for volume = 485320880 0x1ced68b0
    total sectors for embedded volume = 0 0x00

    I do not understand why mac os x does not start, instead the bootcamp partition with Windows 7 works perfectly. Perhaps the problem may depend on the cache? However, the MAC partition I still have 20Gb of free space.

    Now I try to make a copy with Carbon Copy, then I can also replace the hard disk and reinstall everything.

    Thanks.

  62. diddy Says:

    January 31st, 2014 at 1:51 pm

    how do i opt out of the single user mode? when i shut it down i have to start over again :(

  63. darryl Says:

    February 3rd, 2014 at 1:23 am

    Zap the PRAM in your Mac. To do that, start with your Mac turned off. Power on your Mac, and as soon as you hear the status tone being holding down the following four keys on the keyboard:

    Command – Option – P – R

    Keep holding down those keys until you’ve heard the startup tone a total of four times (including the first startup), then release the keys and let you Mac boot up normally.

    Note: If you have a wireless keyboard, make sure not to press the keys until after you hear the initial startup tone. Before that, they keyboard hasn’t been recognized by the Mac, so key presses that happen before that are ignored. With wired keyboards, when you press makes less difference.

  64. Christopher Says:

    February 5th, 2014 at 12:18 am

    Hi,

    Been running the latest version od Snow Leopard for a few years. All of a sudden my computer freezes for 7-10 seconds any time i drag an open window, right click, control click, or click around between open folder/windows.

    Ram is all good memory all good. Little usage going on. No page outs, etc. however, I have several disk permissions that don’t get repaired when I run disk utility or disk warrior.

    I tried single user mode. No problems. Safe mode works great. I have a disk partition running Lion and it works great. However, I want to work in the Snow Leopard partition. Any thoughts on how to resolve these freezing issues?

  65. darryl Says:

    February 9th, 2014 at 4:04 am

    If you’ve already run diagnostics in single user mode, and started in Safe mode, then the nest thing I would do is check for phishing scripts that might be running on your computer in the background. It’s easy to do, and free with ClamXav…but it will take a while depending on the size of your drive. The instructions are on this page on this site:

    http://www.everythingmacintosh.com/tech-notes/identify-and-delete-viruses-with-clamxav/

    Phishing scripts don’t damage your OS, programs, or files. But they send out large volumes of email in the background to mailing lists of recipients that are usually stored on the computer of whoever wrote the script. They do this in the background, using your mail server. Because they’re actively doing what they do in the background, your computer is splitting processor cycles between doing what you’re trying to do on screen and continuing to process the outgoing mail in the background…usually the only symptom is that your Mac will be slower than normal.

    In troubleshooting unusually slow Macs, I have often found and removed 25 or 30 phishing scripts from a single Mac. They usually come in as attachments to an email, and as long as you don’t open the attachment they remain inactive. But even computer techs like me occasionally get fooled by a legitimate looking message I open when my mind is on something else. So although ClamXav may find lots of them, chances are that most are inactive files just taking up space on the drive. You only need one or two active to slow things down.

    Good luck!!

  66. Will Says:

    February 10th, 2014 at 10:33 pm

    Hello, My mac was fine and one day i went to turn it on and found it would not load. I tried a safe boot, then tried single user mode but got I/O Errors and Invalid Node structure errors forever. I put the computer in Target disk mode, transferred the files i want to keep and erased the Hard drive. Trying to load i get the Blinking folder with ?. so i created a recovery HD thumbdrive and ran disk utility, “Disk Utility Was Unable to repair the hard drive”. Is The Hard Drive Toast? Should i buy i new one of have it replaced?
    Thanks.

  67. darryl Says:

    February 10th, 2014 at 11:17 pm

    I/O Errors usually means that the physical disk within your hard drive has areas where the magnetic coating is worn so thing (or scratched away) that those areas aren’t storing data reliably.

    When you buy a standard hard drive of any size, the claimed capacity of the drive is always a bit less than the real capacity. A percentage of the available space is held back as “spare space” that can be used to replace any bad areas of the surface of the disk. As long as the available spare space on the drive is equal to or greater than the space that’s unreliable, the unreliable area can be “mapped out” (meaning never used again), and anything that was going to be written there can be written into the spare space.

    When there is less spare space than the bad space, the drive needs replacement. So here’s what I recommend.

    Erase your drive with Disk Utility. Before you actually click the Erase… button in the window, click on the Security Options… button. Move the slider in the window that appears one step closer to the Most Secure setting. That causes Disk Utility to write zeros once over every sector of the drive…but part of that procedure also tests for unreliable sectors and maps them out, bringing spare sectors into play.

    If there are too many bad sectors (not enough spares), the erase will fail…and you need a new drive.

    If the erase succeeds, try restoring your data again. It should work…

    Good luck!!

  68. Mendel Says:

    February 11th, 2014 at 2:06 am

    Unfortunately I have a problem.

    My SSD is partitioned. If I manually set the Trim command in single-user mode (fsck -ffy), then only the boot partition is trimmed. What must I do to trim other partitions or drives?

    Either way: Thank you very much!!!

  69. darryl Says:

    February 11th, 2014 at 7:43 pm

    Check out this article, which will tell you how to enable TRIM across the board. According to the author, this works in Snow Leopard, Lion, Mountain Lion, and Mavericks.

    http://www.mactrast.com/2011/07/how-to-enable-trim-support-for-all-ssds-in-os-x-lion/

  70. Sascha Says:

    February 23rd, 2014 at 10:55 am

    Hi there,
    I have an older Macbook Pro (purchased in late 2007) that won’t start up OS X. It worked well up until a year ago or so, until the screen started to show a virus like scramble pattern which gradually got worse and finally debilitated the system. I have since bought other Mac’s and was about to throw my old MacbookPro in the bin, since it would no longer start up. I gave it one last try the other day and discovered that my old boot camp partition was still intact and that windows 7 which I installed a couple of years ago still starts up and runs perfectly well – no scrambled screen at all and hence this cannot be a hardware issue. However, I’m still unable to start OS X.
    Here is what I have:
    1. A Macbook Pro from 2007 with an older version of OS X on it (can’t tell which one exactly because I can’t start it up).
    2. A partition with windows 7 which works perfectly fine.
    Here is what I DON’T have:
    1. The stupid software DVD from 7 years ago (come on, seriously…)
    2. A back up of any sort.
    Here is what I have tried:
    1. Safe Mode – does nothing/won’t work/can’t start in Safe Mode
    2. Single user mode (FSK) which worked as explained but did nothing to start up OS X.
    3. Insert other start up DVD’s from other Macbook Pro’s I own (waste of time).
    Here is what happens when I turn on the computer and start OS X:
    1. The chime starts.
    2. Screen goes grey.
    3. Apple Symbol appears.
    4. The little thing bellow spins.
    5. After some time the screens goes blue.
    6. The blank blue screen alternates in different shades of blue and occasionally the little spinning thing shows up.
    7. End of story.

    Any suggestions are welcome…

    Thanks!

    Sascha

  71. darryl Says:

    February 23rd, 2014 at 7:36 pm

    If you have an Apple Store or an authorized Apple dealer or repair center nearby your location, you should be able to bring your old MacBook Pro into them for an OS X reinstallation. If your MacBook was manufactured in 2007, the best version of OS X to run is Snow Leopard (10.6.8). However you can also buy the Snow Leopard installer online at the Apple Store. Because your email address ends in .de, I’m assuming you’re in Germany. Here’s the page for buying Snow Leopard 10.6.8 on your local Apple Store page for €18. Apple will ship you the installation DVD, and you’ll be able to install OS X. Good luck!!

  72. tulga Says:

    March 1st, 2014 at 3:17 pm

    my Macbook pro is doing the same thing where it is just stuck on the grey screen. i tried the safe boot but the loading on the bottom just appears and disappears and it goes back to original. i tried fsck -fy and the first few times it said
    **root file system
    executing fsck_hfs (version diskdev_cmds-540.1~25)
    **verifying volume when it is mounted with write access.
    journal needed to be replayed but volume is read-only
    **checking journaled HFS Plus volume.
    the volume Macintosh HD
    **checking extents overflow file.
    invalid leaf record count
    ( it should be 237 instead of 259)
    **checking catalog file.
    invalid sibling link
    (4, 18099)
    ** the volume Macintosh HD could not be repaired

    ** FILE WAS MODIFIED **

    but now its
    **root file system
    executing fsck_hfs (version diskdev_cmds-540.1~25)
    **verifying volume when it is mounted with write access.
    journal needed to be replayed but volume is read-only
    **checking journaled HFS Plus volume.
    the volume Macintosh HD
    **checking extents overflow file.
    invalid leaf record count
    ( it should be 237 instead of 259)
    **checking catalog file.
    invalid sibling link
    (4, 18099)
    ** the volume Macintosh cannot be repaired it is in use.
    ** the volume Macintosh HD could be repaired.
    /dev/rdisk0s2 (hfs) EXITED WITH SIGNAL 8

  73. Mike Says:

    March 24th, 2014 at 4:50 am

    So I just get an endless grey screen. Starting in single user mode and trying fsck -fy returned:
    ** /dev/rdisk0s2
    ** Root file system
    Executing fsck_hfs (version diskdev_cmds-540.1~44).
    ** Checking Journaled HFS Plus volume.
    The volume name is Macintosh HD
    ** Checking extents overflow file.
    ** Checking catalog file.
    Missing thread record (id = 9697)
    Invalid sibling link
    (4, 4017)
    ** Rebuilding catalog B-tree.
    ** The volume Macintosh HD could not be repaired.

    ***** FILE SYSTEM WAS MODIFIED *****

  74. darryl Says:

    March 27th, 2014 at 10:09 pm

    Hi, Tulga. Wish this had helped. You’ll need to get hold of a third party disk repair utility like Disk Warrior or TechTool Pro. The built in repair routines in OS X are basic and don’t fix everything…when they don’t, the answer is to use a third party utility that’s more capable.

    Disk Warrior is available at aloft.com, TechTool Pro is available at micromat.com. Both are $99.99.

  75. darryl Says:

    March 27th, 2014 at 10:15 pm

    Did you try a Safe Boot, Mike? Start up your Mac while holding down the Shift key. Keep holding the
    Shift key until you see a status bar at the bottom of the screen below the gray Apple and spinning gear. Once you see the status bar you can release the Shift key.

    Most people think of Safe Boot for disabling any third party software that would normally load at startup. A Safe Boot does that, but more importantly in your case, it rebuilds the Launch Databases stored on your hard disk…which, when corrupted, can prevent you from getting past the gray screen.

    If a Safe Boot doesn’t resolve the issue, the next step would be to use a third party disk repair utility like Disk Warrior or TechTool Pro to check and repair your hard disk. The built-in FSCK routine is basic…certainly not the be-all and end-all of disk repair. It fixes the most common problems and works the majority of the time. When it doesn’t, that the time to go third party.

    Disk Warrior is available at aloft.com, and TechTool Pro is available at micromat.com…each is $99.99 I think.

    Good luck!

  76. jeff Says:

    March 30th, 2014 at 2:00 am

    Just want to say THANK YOU SO MUCH :)

  77. Tristan Says:

    March 31st, 2014 at 7:04 pm

    Yes, I’ve done this and everything else to get my mac to boot, but it says it appears okay, and I’ve done shift to go to safe mode, but it goes to the loading screen and the bar disappears in the middle, what do I do? Thanks! oh btw: I have done the pram stuff, and other things, I cannot use disks because there is a disk stuck in the drive and it won’t work even when a disk is out, put a new disk in, it gets stuck, I can’t get this new disk I have in here out, so it wouldn’t work anyways.

  78. darryl Says:

    March 31st, 2014 at 7:42 pm

    If you’re using a Mac laptop, start with the computer powered off. Press and hold the eject key at the upper right corner of the built-in keyboard, and continue to hold down that key while starting up the Mac. Keep holding the key down…the disk in your SuperDrive should eject. The eject button looks like an upward pointed arrow head that’s underlined.

    If you’re using a Mac desktop computer start up the computer, and begin pressing the left mouse button as soon as you hear the startup tone. Keep holding down the mouse button…the stuck disk should eject.

    Once you’ve ejected the disk, you can purchase Disk Warrior or TechTool Pro and repair your hard disk properly.

    Of course if you continue to have problems, you can bring your laptop to any Apple Store. You can find the closest to you by going to apple.com/retail and entering your zip code. I did that for you and it looks like your closes Apple Store is at:

    Apple Store West County
    131 West County Center
    St. Louis, MO 63131

    I checked to see if there’s an Apple endorsed consulting company nearer to you, but it looks like they’re also in St. Louis…at that point you might just as well go to the Apple Store. Of course you’re welcome to send your computer to us, but I’m sure you’d rather have the work done locally. If you decide you do want to send it to us let me know and I’ll provide shipping info. You’ll get your computer back working just fine.

  79. Jerry Says:

    April 14th, 2014 at 12:21 am

    Hi Darryl,

    I did what you stated and read the comments but no one is having the same problem as myself. I get this message after I had renamed my hard drive by right clicking it in “accounts” and then clicking “advanced” then it asked me to restart which I did. After it had restart it gave me this message “logging in to the account failed because an error occurred”. Do you know a solution, I’ve google for almost 4 hours last night and no one has a resolution for me. Your post is the only post so far that gave me a correct input at root.

    I did what you mention and my hd is ok. But I still cannot log in in safe mode or normal. I wasn’t given a disk when I purchased the laptop in 2010. Honestly, I don’t want to do a format I have files I need for school that I cannot afford to lose.

    Any type of help is appreciated. I want to tackle it myself before going to apple.

  80. darryl Says:

    April 14th, 2014 at 6:19 pm

    It sounds as though in changing your user name (after clicking Advanced), you didn’t set exactly the right name for your home folder. As a result, when you boot up, OS X tries to locate the home folder corresponding to your user name, but there isn’t one…so boot up fails. Talking you through fixing this is way beyond the scope of this blog…I recommend either sending your laptop to us (we’ll turn it around in about a day), or taking it to your nearest Apple Store or an authorized Apple service center.

  81. Kyle Says:

    April 21st, 2014 at 2:13 pm

    Ok so I have tried numerous steps to boot my MacBook Pro. I have tried safe mode and the recovery partition both of which result in getting a blank blue screen. Normal start up gives me a grey screen but I am able to boot in to single user mode. I ran the /sbin/fsck -fy command and I get the drive is ok message followed by file system was modified. I go to reboot and I still get stuck on either a grey or blue screen. I also saw something in the text about a kernel panic. Is there any way to resolve the kernel panic issue and will that fix my Mac, I also believe I know what application caused the failure in the first place can I remove it in single user mode and will that possibly fix my Mac. My last question is can I possibly back up my hard drive to an external drive from single user mode before I would reinstall my OS, I have a lot of important school work on the hard drive and my graduation may depend on being able to retrieve my work

  82. darryl Says:

    April 21st, 2014 at 3:56 pm

    Based on what you’ve told me, what I’d do would be to install OS X on an external hard drive, then boot your MacBook Pro from that drive. When you get to the desktop, both the external drive and your internal drive should be accessible.

    (If you don’t see their icons on the desktop, click Preferences in the Finder menu. In the Finder Preferences window, click on the General button at the top, then make sure the boxes for Hard disks and External disks are clicked.)

    You can then copy all your files from the internal drive to the external. Once you’ve saved all your files, you can safely do a clean installation of OS X on the internal drive, create your user account, and copy back all your files.

    Good luck!!

  83. Kyle Says:

    April 21st, 2014 at 6:14 pm

    Ok I tried what you said but when I try and boot the OS from the external drive I either get a grey screen or blue screen. Is it safe to say that my logic board is toast or am I not doing something correctly

  84. miriam Says:

    April 26th, 2014 at 12:08 pm

    how can i fix my macbook pro the maintosh is damage

  85. darryl Says:

    April 26th, 2014 at 5:07 pm

    I don’t have enough information to make a recommendation for how to repair the Mac…what’s wrong with it?

  86. N Says:

    May 5th, 2014 at 1:25 pm

    Hi, I have an early 2011 MacBook Pro running on Snow Leopard. A few days ago the screen started to glitch and freeze to what appears to be randomly. I’m not sure what triggered it. So I booted it on safe mode, and now the laptop runs slower than ever. Sometimes I don’t even manage to start it up and only directed to grey apple screen followed by a blue screen. I ran the disk utility and followed the steps above, it says that volume was repaired, but when I rebooted it, I was led to the blue screen again. When I managed to turn my laptop on, I ran the disk utility again, and it still tells me that the volume is corrupted. What should I do now? Thanks!

  87. darryl Says:

    May 5th, 2014 at 6:31 pm

    Sorry you’re having a problem.

    Your next step is to use a third party disk repair utility like Disk Warrior or TechTool Pro to repair your hard disk. The built-in repair utility (Disk Utility or using fsck in single user mode) is a basic repair utility…repairs the fundamentals, but doesn’t dig as deeply into the hard disk’s directory as the third party utilities do.

    Disk Warrior is $99.95 at http://www.alsoft.com/diskwarrior/, and that allows you to both download the program immediately, and they will also send you a bootable DVD…which is what you’ll really need. TechTool Pro is $99.99 at https://www.micromat.com/store and also comes on a bootable DVD.

    You’ll need to boot from the DVD and run whichever program you buy. You can only make limited repairs to the disk that contains the operating system the computer is currently using to run, so by booting from the DVD you’re running from OS X on the DVD…which leaves your internal drive free for whatever repairs are necessary.

    Good luck!!

  88. Vale Says:

    May 6th, 2014 at 11:14 am

    Hi Darryl,
    I owe a MacBookPro (2007), 15″ 2.2 GHz Intel Core 2 Duo, Mac OS X 10.5.8 installed. I tried to repair my HD with Utility Disk but it failed, so I tried with fsck. The message I got are:

    disk0s2: I/O error.
    Invalid record count
    (4, 34348)
    **Volume check failed
    ***** FILE SYSTEM WAS MODIFIED *****

    And then every time I try fsck again I get:

    disk0s2: I/O error.
    Invalid record count
    (4, 34348)
    **Volume check failed
    /dev/rdisk0s2 (hfs) EXITED WITH SIGNAL 8

    What does it mean? How can I fix it?
    I tried to repair the HD because I did a backup with Time Machine yesterday (a complete backup on an external HD, empty and initialized) and I wanted to do an incremental backup today, ’cause my HD is 80,7GB but the backup folder is 76,86 GB. But Time Machine keeps preparing the backup but never starts it.

    (Sorry for my English, I’m not great at it)

  89. darryl Says:

    May 6th, 2014 at 1:56 pm

    The important information in what FSCK told you was, “disk0s:I/O error.” That tells me the internal hard disk is failing, because the I/O error means that the internal hard disk is not communicating reliably with your computer. Fortunately, your disk still seems to be working well enough to have allowed you to get a Time Machine backup yesterday, so at least we know that we have all your files safely backed up.

    I would recommend taking your computer to one of the Apple Store’s in Milano, or to any authorized Apple repair center to have the internal disk replaced.

    Good luck!!

  90. Vale Says:

    May 7th, 2014 at 11:26 am

    Thank you vey much for your reply.
    In your opinion, would it be possible to install a SSD in my Mac? Or it’s better a HDD? I called the repair centre and they told me that they probably have to use a compatible HD because my Mac model is old. So I was thinking about getting a SSD instead. I know my model isn’t very fast so I can’t use the full speed of a SSD, but I read different opinions that said it’s worth it anyway.

  91. Vishal Says:

    May 9th, 2014 at 5:29 am

    Dear Editor,

    I just want to sahre with you that Stellar Volume Repair is a fine utility that creates a bootable dvd for corrupted Mac partition & resolves nightmarish disk errors such as Invalid B tree node. I hope this knowledge will help you evaluate this tool & write something on it for your users.

  92. darryl Says:

    May 10th, 2014 at 7:05 pm

    I’m happy to download the demo and take a look, Vishal. If our staff likes it, we’ll mention it in our posts.

  93. Vishal Says:

    May 14th, 2014 at 5:56 am

    Thanks Darryl, I am hopeful that staff will like this utility to include in the post. We have a new version coming soon for the same. Will let you know if you want to review it.

  94. rahemeen khan Says:

    May 20th, 2014 at 12:02 am

    How do you back up files from a laptop that isn’t working? I have another functional mac, please let me know if there is any way to transfer files or anything i can do to recover them. I am very grateful.. :)

  95. darryl Says:

    May 20th, 2014 at 4:36 am

    I would try removing the internal hard drive from your non-working laptop and installing it into an external USB drive enclosure…which turns that internal drive into an external USB drive. Once it’s removed, it drive simply plugs right into the connector inside the external enclosure. Then simply use the included USB cable to plug the enclosure into your other computer. If the drive itself is working, it should pop right up on your desktop and you should be able to copy any or all the files it contains.

    If you’re uncomfortable removing the drive from the old computer yourself, a local computer shop should be able to do it for you…or you can always send it to us and we’ll remove and recover it.

    Based on your IP address, it seems as though you’re in Toronto, Canada. An example of the external enclosure I’d use is this one at Best Buy:

    http://www.bestbuy.com/site/dynex-2-5-serial-ata-hard-drive-enclosure-black/5190553.p?id=1218623897772&skuId=5190553&st=drive%20enclosure&cp=1&lp=2

    Of course you don’t have to use that particular one…just search for 2.5″ USB drive enclosures with Google and you’ll find many, even less expensive than the Dynex brand in that example. Any should work for your purpose.

    If that internal drive is no longer functioning, you might still be able to have the data recovered, but it would have to be done by someone who specializes in drive recovery. If the disk has failed mechanically, a drive recovery company like http://drivesolutions.com can repair the drive mechanism enough to copy the data to another hard drive and return it to you. The price for that kind of recovery would depend partly on the size of the drive and how much repair work needed to be done to access the files. Drive Solutions will give you a detailed estimate in advance, so contact them at their web site if simply installing the drive into an external enclosure doesn’t work.

    Good luck!!

  96. Ally Says:

    May 22nd, 2014 at 8:08 pm

    Hi Darryl, have a serious problem with my MacBook Pro. Purchased it in 2011-was completely fine till yesterday . Started off with a white screen and the spinning wheel for two hours – I restarted a couple of times and pressed option P R and command a couple of times once safe mode wasn’t grttingn activated. Tried command plus r and connected to apple network via wifi. Disk utility did a disk repair and it said after three attempts that the disk cannot be repaired and I should restore data and reinstall my OS.. I restarted and it took me to safe reboot mode. It asks for my password- here’s the strange part, I’ve never set an admin password for my account so tried all sorta of combinations but didn’t work. I then tried command plus so to run on single user- Running FSCK to change my admin password but it said I/O error and now I’m stuck . What do I do next? My data is extremely important to me as I have no backup of anything for the past 4 years. Help please!!!

  97. darryl Says:

    May 22nd, 2014 at 8:48 pm

    The I/O error (input/output error) indicates that your internal drive is likely failing…that there is a problem either reading from or writing to the drive…or both. That means you’ll need to replace that internal drive.

    If I had that computer in my office, I’d try a few things.

    1. Boot the computer in target disk mode (start up while holding down the letter T on the keyboard). You’ll see a gray or blue screen with the Thunderbolt and FireWire symbols moving around the screen. When booted this way, your computer behaves just as though it were an external Thunderbolt or FireWire hard drive. You can now use a Thunderbolt or FireWire cable to connect your computer to another Mac, and if the internal drive is working sufficiently well it will mount on the screen of the other Mac as an external drive. You can then copy all your data to another external drive.

    2. Purchase a copy of Disk Warrior (aloft.com, $99.95 US), which is an excellent disk diagnostic, repair, and recovery program. It comes on a bootable DVD that you can use to boot your computer…it will boot directly into the Disk Warrior program. You can then use Disk Warrior to run a diagnostic on the internal drive. Disk Warrior will create a brand new, optimized directory for the drive in RAM, then display a preview image of the repaired drive on screen…all without attempting to write anything on your actual drive (to prevent any further damage from occurring). If you attach another hard drive, you should be able to copy all of your data from the internal drive to the external.

    3. If those methods fail, I strongly urge you to get your computer to a professional disk recovery company so they can recover your data. I’d suggest you send it to Everything Macintosh, but we’re in the US…I don’t think that makes any sense. It appears from your IP address that you’re in India. I Googled data recovery services near where you are in India (you can do the same thing) and found a few…one of which is http://www.datarecoverymumbai.com.

    Once you have your data safely recovered to an external drive, install the replacement drive in your MacBook Pro and install OS X (preferable the same version you were running). If you were able to recover your data using #1 or #2, you should then be able to use Migration Assistant to restore your data and programs to the new disk. If you had to use a data recovery company, you may have to copy the data to the new drive manually because it may not be organized on the recovery drive in the same way it was on your original drive.

    I wish I could help more…good luck!!

  98. SniffinCrayons Says:

    May 26th, 2014 at 2:32 pm

    Daryl you are a life saver!!! Thank you so much, I had quit half way through partitioning my HD for over 200GB. Rebooting in single user mode saved it.

    THANK YOU SO MUCH!

  99. Dimas Says:

    June 10th, 2014 at 11:01 pm

    Hello Darryl,

    I tried your suggestion and says its fine.. but after rebooting Im stuck at Apple logo.. when I try to entering the safe mode, it’s still stuck at logo apple.. any suggestion?

  100. darryl Says:

    June 11th, 2014 at 4:51 pm

    There are a couple of things you can do.

    A. If you’re running OS X 10.7 or later, boot into the Recovery Disk and reinstall OS X. To do that

    1. Restart your Mac. Once you hear the startup chime, being holding down the Option key on the keyboard. Holding down the Option key takes you to a gray screen with big icons for each of the available drives connected to your Mac from which it’s possible to boot up. Under Mac OS X 10.7 or later, you’ll always see at least your internal drive and the Recovery Disk.

    (NOTE FOR WIRELESS KEYBOARDS ONLY: If you have a wireless keyboard, you may have to try this a few times, adding an additional second or two wait after the startup chime each time. The Mac recognizes wireless keyboards during the boot process when it loads the BlueTooth driver software…if you press the Option key on a wireless keyboard before the Mac has recognized it, the Mac won’t know the key is pressed when it finally recognizes the keyboard…so it attempts to start normally instead of giving you the ability to choose which disk to start from. So with a wireless keyboard, if you see the gray apple, turn off the computer, start up again, and wait slightly longer before pressing the Option key.)

    2. When you see the gray screen with icons for your internal drive and the Recovery Disk, use your mouse or arrow keys to select the Recovery Disk, then press the Return key to boot from that disk.

    3. When you get to the desktop, you’ll see a window offering you the choices of Restore from Time Machine Backup, Reinstall OS X, Get Help Online, or Disk Utility. Click on Reinstall OS X, then click the Continue button.

    4. Follow the prompts to reinstall OS X. This will not affect your data or programs…it just reinstalls OS X itself, correcting any issues with your existing installation. Once that’s done, you should be able to boot up.

    B. You can try using a third party disk repair utility to resolve the issue that’s preventing your Mac from getting beyond the gray apple. I’d recommend a utility like Disk Warrior, which is easy to use and corrects most problems. Disk Warrior is also useful for detecting a failing hard disk, because as it scans your disk to determine whether it’s healthy or not, if the disk has bad sectors on it it will say, “Progress slowed due to disk malfunction”. If you see that in Disk Warrior, you should boot from another disk, copy off your files, replace the hard disk, and restore the files.

    Good luck, Dimas!

  101. Dimas Says:

    June 12th, 2014 at 2:31 pm

    it’s still stuck at the gray screen when I choose the recovery disk.. yesterday I was able to fix it, now it’s error again and right now I cant even go to the single user mode, it says error 19.. any idea about this?

  102. Pete Bowe Says:

    July 2nd, 2014 at 9:10 am

    If the drive will still not mount after fsck fails, this worked.

    CMD+S and start button for single user mode.

    type: /sbin/mount -uw /
    *press enter*
    type: chmod 775 /
    *press enter*
    type logout
    *press enter*

    It should then boot and go to login.
    This is courtesy of qwea44 on youtube and it works at least long enough to back everything up.

    After that I changed the hard drive.

  103. Victoria s Says:

    July 3rd, 2014 at 7:43 am

    When i reboot by holding option key it takes me to the screen with only one big icon of Macintosh HD. No recovery disc or anything. When i click on it it goes strain to blue screen with the loading wheel. What do i do next?

  104. Vishal Says:

    July 4th, 2014 at 10:58 am

    Hi Sir, Any update on our product inclusion in the above article? To let you know Stellar Volume Repair is renamed as Stellar Volume Optimizer. it repairs corrupt Mac disk. Just let me know if you got time to review the app. Or if you want to review the latest v2.0 then please feel free to mail me.

  105. Dave Says:

    July 7th, 2014 at 11:03 am

    So I have multiple MacBook problems going on the latest resulting from my own stupidity. I have an old MacBook pro Intel core duo processor running snow Leopard. Or at least it was. A few months back a friendof mine cracked the screen and it has gotten to the point where only the top 1/6th of the screen is visible. That’s no problem I have been connecting it to an external monitor. Foolishly though I was rummaging through some files and apps a friend put on my system and I don’t know what I was thinking but I installed a . pkg called 64bit knowing that my system can only handle 32bit software. Once the computer restarted it brought me to my regular login page. I would go to login it would accept the password and then loop right back to the login page. Login loop, login, loop. Tried a command in SUM to get me running 32bit again. Tried holding 32 while I boot to no avail. I’ve run /sbin/fsck – fy countless times and while at first it said some things were modified it still looped. Now it says the volume is ok each time. Ran across a command to create a new administrative account and now instead of the login screen I have the OSX welcome video on a constant loop and can’t get past that. Computer cannot boot via safe mode. Single user mode works but I am limited to seeing only the very top of the screen. Obviously I don’t know what I’m doing in single user mode and my original install disk is scratched up so badly it wouldn’t be readable if my optical drive still worked anyway. Wondering if you had an idea as to anything I could do via Single user mode to remedy everything I’ve messed up knowing that I’m a novice when it comes to commands.

  106. Frans Kemper Says:

    July 8th, 2014 at 11:12 pm

    Hello Daryl,
    First I like to thank you for the useful lessons I get from your support.
    Recently I updated my 15″ MacBook Pro (8,2) to Mavericks.
    It ran fine until this morning when I was copying some CD’s into the iTunes library. The screen turned black and I have not been able to boot the MBP up.
    Whatever I do, after a short screen with Apple logo and spinning wheel the screen goes grey and freezes.
    I tried all the start up options with the same result.
    Even the bootable USB stick and Firewire HDD with a Carbon Copy Clone are not working. Also the original install DVD does not work.
    Only thing that seems to be working is the Single User Mode.
    I ran the /sbin/fsck -fy and no problems were reported.
    I also run the fsck_hfs -y -Rc -d /dev/disk0s2 several times and every time is appears that something has been repaired.
    The online Apple extensive hard ware test came back clean.
    Do you please have any suggestions how I can get the MPB booting again and running?
    Thank you so much,
    Best regards,
    Frans Kemper

  107. darryl Says:

    July 9th, 2014 at 7:59 pm

    Have you tried booting in Safe mode? Start up your Mac and immediately begin holding down the Shift key on the built-in keyboard. Keep holding down the Shift key until you see a status bar at the bottom of the screen below the gray Apple. Safe booting disables third party software that loads at startup time, and also rebuilds the Launch Database stored on your hard drive. Corruption to the Launch Database can prevent booting, so rebuilding that is exactly what I’m trying to accomplish with the Safe boot. Let me know what happens, Frans.

  108. darryl Says:

    July 9th, 2014 at 8:05 pm

    Although I have no idea what actual software you were installing with that 64bit software installer, what I’d do in a case like this is to boot your Mac from an external bootable USB or FireWire hard drive. While booted that way, you should have access to your internal drive…so immediately back it up in its entirety. Then I’d format the internal drive, use Migration Assistant to copy only your user data from the backup to the internal drive, and finally reinstall all your programs from their original installers. The reason I don’t want you to use Migration Assistant to copy the applications as well is that if you did install a rogue application, or if one of your applications was damaged by your 64bit installation, you won’t be copying it back onto your internal drive. After doing what I’ve suggested, your Mac should boot up normally. Good luck!!

  109. darryl Says:

    July 9th, 2014 at 8:08 pm

    It could be that you’re running a version of OS X earlier than 10.7. The Recovery Disk was a feature added starting with OS X 10.7. If you’re running a version earlier than that, refer to the article on this article:

    http://www.everythingmacintosh.com/tech-notes/repair-your-hard-disk-in-single-user-mode/

    If repairing your disk in Single User Mode doesn’t resolve the issue, you’ll need to use a third party utility like Disk Warrior or TechTool Pro to repair the disk.

  110. Lincoln Sills Says:

    July 18th, 2014 at 6:35 am

    2010 MBP with Mt Lion installed that hangs on gray screen…

    I’ve reset NVRAM and SMC.
    I’ve ran /sbin/fsck -fy 3 times and rebooted into Safe mode , all ending in Gray Screen.
    Created a 16GB USB drive that I installed Mt Lion on, then booted to USB Mt Lion and installed Disk Warrior on the USB drive. The only problem is that Disk Warrior can’t see the HD or anything outside of the USB drive. Can you point me in the right direction? Thank you for this AWESOME and informational post!!!

  111. Daniele Says:

    July 22nd, 2014 at 3:25 pm

    Dear Darryl,
    Mavericks, and symptom is: boot with spinning gear, endless.
    I followed your guide about singe user mode. It repaired, then when rebooting,
    -safemode gets to 1/3 of the bar, then spinning gear.
    -verbose mode (cmd+V) gets to fsck_hfs and then says: realpath /none no such file or directory, and freezes.
    -option key, boot from timemachine: spinning gear.

    Any ideas?

    Thanks!
    Daniele

  112. darryl Says:

    July 22nd, 2014 at 3:51 pm

    The fact that your Mac attempts to boot and gets as far as the gray screen tells me that it’s recognizing the presence of the hard drive and reading from it. It gets to a point during the boot up where it’s no longer able to find the files it needs to continue…hence it gets stuck on the gray screen. That tells me the directory for the drive (the index that lets the drive find the files requested) is damaged badly enough so that it was beyond the capability of FSCK to fix.

    If Disk Warrior, running on the 16GB thumb drive, didn’t even see the drive, the directory is probably damaged severely enough so that it’s not transmitting any information to Disk Warrior about how it’s formatted, where to find the software drivers stored on the drive…so Disk Warrior doesn’t even recognize it. My next step would be to attempt to recover the drive’s files using a disk recovery utility like Data Rescue.

    You can run Data Rescue (available at http://www.prosofteng.com/products/data_rescue.php for $99) either from your 16GB thumb drive or the DVD it comes on, but you’d need to connect an external drive with capacity equal to or greater than the amount of data to be recovered from the internal drive. Once Data Rescue locates all the files it can, it asks you to select another drive to which the files will be copied.

    Data Rescue scans the drive several different ways…once looking for whatever directory information it can find scattered on the drive, once ignoring the directory altogether and building its own by scanning the actual files it can recognize on the disk. The files it recovers based on directory info come back with their file names, and in their correct folders. Files located without directory information are often recovered into generic folders with names like Microsoft Word files, TIFF files, PDFs, etc. They may or may not have names…depending on how much information Data Rescue was able to salvage during its scan. However you can open the files and rename them, then move them into their proper folders…which may be a lot of work if the directory is very badly damaged, but at least you don’t lost the files themselves.

    If this is more than you want to take on, you can always send us your Mac and we’ll do the recovery here. Just let us know.

    Good luck!

  113. Daniele Says:

    July 22nd, 2014 at 3:54 pm

    Thanks for the prompt reply. However, it is a bit more subtle than that. fsck in cmd+S mode works, and I can see all my files in command mode.
    It is in verbose mode (and, I suppose, in safe mode) that I get into the “realpath” mistake.

    ????

  114. darryl Says:

    July 22nd, 2014 at 3:59 pm

    Next step is to try using Disk Warrior, available at http://www.alsoft.com/diskwarrior/ for $99.95 (you can download it as soon as your payment is processed, and they’ll also send you a bootable DVD with the program installed). Disk Warrior is a far more comprehensive directory repair program than the built-in FSCK than provide. It works most of the time.

    If you have an external bootable hard drive, you can copy Disk Warrior onto that drive, boot from that drive, and run Disk Warrior from that drive. Once it scans your internal drive it will display a disk of the problems found and fixed. It actually fixes the problems on a substitute hard disk directory for the drive that’s created in the RAM of your computer…so if it doesn’t work, nothing has been changed about the problem drive at all. In that same screen, there’s a Preview button that mounts an image of the drive using the directory stored in RAM…this shows you exactly how the drive will look if you choose to replace the existing directory with the optimized directory Disk Warrior has created in RAM. It’s a way to make sure that the repair drive still contains all you files. If so, you can click the Replace button, which writes the optimized directory to the hard disk, replacing the old damaged directory.

    If the disk is sufficiently damaged that Disk Warrior can’t repair it, but can display the preview image, you can back up all your files from the preview image to an external drive…essentially recovering the drive.

    When a utility like Disk Warrior fails to fix the drive, the next step is to recover your files using a disk recovery utility like Data Rescue, available from http://www.prosofteng.com/products/data_rescue.php for $99.

    You can also send you Mac to us for recovery if you don’t want to take on all the work…just let us know if you’d prefer that option.

    Good luck!!

  115. darryl Says:

    July 22nd, 2014 at 4:01 pm

    In that case, I’d simply back up your hard drive in single user mode to an external drive using a standard backup program like Carbon Copy Cloner or SuperDuper!. Then reformat the internal drive, and copy all your files back. This creates a completely new, clean directory on the internal that should eliminate the problem altogether. And it’s a lot cheaper than buying Data Rescue!!

  116. JP Says:

    July 23rd, 2014 at 3:35 pm

    Dear Darryl,

    I have a big problem with my Macbook 2008 (Black).

    Yesterday, I had to shut down my laptop by pressing the power key down for 2-3 seconds.

    My problem is that I can log on, but my Macbook (2008; Black), cannot go past the default wallpaper (purple aurora). It is just stuck and the machine does not load anything. I can still control the brightness and volume, but nothing else.

    I tried a few things first:

    Apple Hardware Test: Both tests revealed no errors.

    PRAM: Could not access the PRAM Mode. I tried the Command+Option+P+R, but I did not see anything even after I waited for four rings.

    Boot Mode: Same problem, able to log in but nothing happens after.

    Start Up Method: Could not access the mode because my CD-ROM keeps ejecting the installation disc.

    Select Start Up Volume: The only icon I could see was my HD. No other icons.

    Note:
    I shut down with a couple of external harddrives still running.

    I am running without a battery.

    Currently has a very low storage space.

    CD-ROM is damaged; keeps ejecting all types of CD/DVDs.

    No other upgrades were done, just early-2008 specs.

    I believe my laptop is OSX 10.5.8, no further upgrads were done to this machine.

    Previously had no major problems.

    I have tried the FSCK and my HD seems OK and it said that it had a repair done. I’ve also tried the step of Safe Boot; it did not work but a pop-up box stated something about Cache and something unnecessary.

    In addition, I am not quite sure in which mode it was, but I received another pop-up box telling me that Java Disabler quit unexpectedly.

    Any clue as to why I am facing this problem? Also, I was thinking of formatting the machine, but my cd drive keeps ejecting any type of cd. I just cannot re-install the OSX even if I wanted to.

    Any help would be greatly appreciated, thank you in advance.

  117. darryl Says:

    July 28th, 2014 at 1:59 pm

    Based on your description of the symptoms I think reinstalling OS X is the way to go, but you can’t do that because your CD/DVD drive doesn’t work. If I were in that situation, I’d take my MacBook to the nearest Apple Store or authorized Apple service center. Based on your IP address, it appears that you’re in Seoul. There is an authorized Apple service center at Coex Mall, and they should be able to resolve the problem by installing OS X from a hard drive.

    I would also ask whether you can purchase the OS X installer for your computer on a USB thumb drive or external hard drive so you can reinstall it yourself if this ever happens again.

    One more thing to consider. Your MacBook is about 6 years old at this point. Logic boards in any computer dry out and become brittle over time, as do the solder joints that hold electronic components to the logic board. The average life expectancy for a hard drive is about 5 years. Of course in both cases, I’ve seen some computers and drives working after 20…and some fail within the first year. The question is whether you’re comfortable trusting your ability to function to a MacBook somewhat beyond its prime. It’s a decision only you can make, but I’d recommend considering replacing that MacBook in the not-too-distant future.

  118. Arun Menon Says:

    August 1st, 2014 at 1:11 am

    Hi Darryl,

    Am using macbook pro mid 2012 13 inch.
    Yesterday I got the white screen with the apple logo and the loading spinner below.I tried the steps that is mentioned however i am not getting the root prompt. the last few lines i got is as below.

    dyld: Library not loaded: /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
    Referenced from: /bin/launchctl
    Reason: no suitable image found. Did find:
    /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation: stat() failed with errno=5
    /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation: stat() failed with errno=5
    com.apple.launchd 1 com.apple.launchctl.System 2 The System bootstrapper has crashed: Trace/BPT trap: 5

    Please advise on what needs to be done???

  119. darryl Says:

    August 2nd, 2014 at 4:42 pm

    Two things to try. First, wait a little bit longer. During a safe boot, the Mac is actually reading system info from the hard disk, and if the hard disk needs repair that may take a few minutes. If after 5 minutes you see the black screen with white lettering, but the #root prompt is still not the last item, try pressing the Return key. Sometimes that will bring up the #root prompt.

    If that doesn’t work, try doing a Safe Boot. Start up your Mac, then immediately begin holding the Shift key on the built-in keyboard. Keep holding down that key until you see a status bar appear at the bottom of the screen below the gray apple. Once you see the status bar, you can release the Shift key. Doing this rebuilds the critical Launch Database on your hard disk. You should eventually come to the login screen…even if you normally boot directly to your desktop. Enter your password, get to the desktop screen, then immediately reboot without holding down any key…a normal boot. If that resolves the issue, you’re all done.

    If the issue isn’t resolved at that point, you should use a third party disk repair program like Disk Warrior or TechTool Pro to fix your hard disk. Read through some of the posts on this page to find out how to get Disk Warrior or TechTool Pro.

    Good luck!!

  120. Johnny Says:

    August 14th, 2014 at 1:39 pm

    Hi Darryl.

    I’m stumped!

    I have a Rev A MacBook Air which is suffering the Grey Screen of Death….

    To date I have (in order):
    Reset PRAM
    Reset SMC
    Safe Booted
    Single User Booted and run fsck (All ok)
    Safe Booted
    Verbose Booted (I/O Errors)
    Attempted to run AHT via Remote Install

    the last solution attempt is the one which is troubling me: As
    I can login to my Airport Network and access the OSX install disk, i get the usual spinning globe, but then I once again get the grey screen of death…

    Any ideas/suggestions?

    Many Thanks

    JB

  121. Bianca Says:

    August 21st, 2014 at 3:24 pm

    Thank you sooooooo much!
    It took a few minutes and I got scared with what I was reading: “looking for missing data on lost and found directory” and “no matching data was found”.
    Then, I waited a little more, it looked for the data again and I got the FILE MODIFIED message!
    Reboot was fine!
    I am in Brazil and they would charge me so much to fix it!
    Saved my life!

  122. Will Seng Says:

    August 30th, 2014 at 6:43 pm

    Got the following, to me contradictory, messages:
    “The volume Macintosh HD could not be repaired after 3 attempts.” and “File system was modified.”

    When I typed “reboot” and pressed the Return key, my MacAir wouldn’t start at all. Before the normal start-up tone, there was a buzz. All I get is the apple and the rotating dial. I’ve done a forced shut down and start up several times, but no improvement.

    Before I contact the Disk Warrior, is there anything else I can do?

  123. darryl Says:

    August 30th, 2014 at 7:01 pm

    Based on what you said, I believe there is likely a problem with the flash drive in your MacBook Air…it will probably have to be replaced. If this were my MacBook Air, my next step would be to take it to your nearest Apple Store or an authorized Apple Repair Center. Based on your IP address, you’re in or around Pleasanton, CA. There is an Apple Store at Stoneridge Mall, One Stoneridge Mall, Pleasanton, CA 94588. Call or go online to apple.com/retail, enter your zip code to find your closes store, and make an appointment with the Genius bar to bring your Mac in for diagnosis. This is a known issue with the flash drive in some MacBook Air models, and Apple has an extended service program for replacing those drives free. You can read about this extended program here: http://www.apple.com/support/macbookair-flashdrive/. I hope you have a backup…and good luck!!

  124. darryl Says:

    August 30th, 2014 at 7:02 pm

    This is exactly why we post! It makes us happy when we help!

  125. darryl Says:

    August 30th, 2014 at 7:17 pm

    This sounds as though you may have a hardware issue, Johnny. At this point, your best bet is to take your MacBook Air to an authorized Apple Repair Center. Apple does have an service extension for free replacements of defective internal flash drives in some MacBook Air models. If yours qualifies, the replacement will be free.

    Based on your IP address, it looks as though you’re in Dublin. I don’t think Apple has an Apple Store in Dublin, but there are several authorized Apple repair facilities:

    • COMPU B
    111 GRAFTON STREET,
    DUBLIN D.2.
    iPadMaciPodApple TV

    • ICONNECT LIFESTYLE LTD
    ARTHUR COX BUILDING, EARLSFORT TERRACE
    D2
    iPadMaciPodApple TV

    • TYPETEC LTD
    UNIT G6 CALMOUNT BUSINESS PARK
    DUBLIN 12
    iPadMaciPodApple TV

    • COMPU B
    UNIT 12, DUNDRUM TOWN CENTRE, SANDYFORD ROAD
    DUNDRUM D 16
    iPadMaciPodApple TV

    • COMPU B
    UNIT 226, BLANCHARDSTOWN SHOPPING CENTRE
    BLANCHARDSTOWN D15
    iPadMaciPodApple TV

    • MACTIVATE LTD
    NORTHWEST BUSINESS PARK, UNIT 13, NORTHWEST CENTRE
    BLANCHARDSTOWN, DUBLIN 15
    iPadMaciPodApple TV

    • ICONNECT
    LIFFEY VALLEY SHOPPING CENTRE, FONTHILL ROAD
    CLONDALKIN D22

    Hope you have a backup! Good luck!

  126. Stalo Nic Says:

    August 30th, 2014 at 9:38 pm

    Hi,
    I’ve started my mac using single user mode, I got ‘system Macintosh HD is ok’. I reboot, enter, my computer goes to the grey scree with the logo, then to a blue screen and it stays there for ever!

    What can I do next?

  127. Will Seng Says:

    August 31st, 2014 at 12:52 am

    Yes, Daryll, I sent you the question and I’m now thanking you on my ever reliable iBookG4!

    Will follow your advice and make an appt. at the Genius Bar at my nearest Apple store, downtown SF. By the way, your site was recommended to me by my personal geek at MacKeeper.

    Will

  128. darryl Says:

    August 31st, 2014 at 3:27 pm

    The next step is to try booting in Safe mode. Doing that rebuilds a critical database stored on your hard drive, and rebuilding it often resolves the blue screen problem. To start in Safe mode, begin with your Mac turned off. Turn it on, and begin holding down the Shift key on your keyboard. Keep holding down the Shift key until you see a status bar at the bottom of the screen below the gray apple. As soon as you see the status bar, you can release the Shift key.

    A few things to know about safe booting. First, it takes longer than normal booting because the Launch Database is being rebuilt…don’t panic if it seems to take a while. Second, even if you normally go directly to your desktop, whenever you safe boot, you’ll got to the Login screen, where you must select your user account and enter your password to go to the desktop. Third, if you’re computer is a Mac laptop, you can begin holding the Shift key immediately after pressing the power button. If you’re computer is a Mac desktop, and you’re using a wired keyboard, the procedure is the same.

    If you’re using a BlueTooth keyboard, wait to press the Shift key until the screen lights up. The Mac doesn’t establish its connection to wireless keyboards until after the bluetooth driver loads, so if you press the Shift key before that the Mac won’t be aware of it…and will try to boot normally instead of into Safe mode. If that happens, just shut off your computer and try again, waiting a little longer before pressing the Shift key.

  129. Stalo Nic Says:

    September 1st, 2014 at 1:23 pm

    Hey Darryl!
    I’ve tried safe mode too. I waited for the blue screen for more than an hour and then I shut the
    i-Mac down.

  130. Stalo Nic Says:

    September 1st, 2014 at 1:25 pm

    Safe mode didn’t work either..should I wait longer?!
    Is there anything else I can do?

  131. j Says:

    September 9th, 2014 at 2:16 am

    I have a 2009 desktop 10.8.0 which was perfect -in single user mode I saw – the volume macintosh he could not be repaired and then file system modified so I asked it to Reboot and now I’m back at the Grey screen. So I tried safe boot and saw disk0s2 I/O error and then eventually saw the could not be repaired message again. It continues on to launch_msg (): socket is not connected

    What is the best next step? I only have a time machine back up.

  132. darryl Says:

    September 10th, 2014 at 2:47 am

    You gave me a clue when you said this, “I tried safe boot and saw disk0s2 I/O error…”

    The I/O (input/output) error means there’s something not right with your drive. It might be that some of the data storage compartments (we call them sectors or blocks) aren’t storing data reliably, or it might be that your drive is beginning to fail mechanically. Here’s what I’d do presuming your Time Machine backup is up to date.

    1. Restart your Mac, and as soon as you hear the startup chime begin holding down the Option key on the keyboard. You should see a gray screen with a big icon for each bootable drive connected to your computer. Even if you have only your internal drive connected, you’ll see that drive plus another called Recovery HD. Double-click on Recovery HD to boot your Mac from that drive.

    NOTE: Recovery HD is actually a separate, bootable partition on your internal drive that contains Apple utilities that can restore your main partition from a Time Machine backup, reinstall OS X, or run Disk Utility on your main partition as though you’re booted from a separate hard drive.

    2. Double-click on Disk Utility in the OS X Utilities window to launch Disk Utility.

    3. In the Disk Utility window, click on the actual name of your hard drive in the column at the left side, then click the Erase tab in the main window. The Format menu should say Mac OS Extended (Journaled), and the Name should say the name of your hard drive…you shouldn’t have to change either of those things.

    4. Click on the Security Options… button. In the new Security Erase Options window, move the slider from the extreme left (marked Fastest) one click to the right. That sets Disk Utility to write zeros to every sector on your hard drive during the erase process, and that process also verifies the reliability of every sector on the drive, and maps out any sectors that fail. Click the OK button to go back to the Erase window, then click the Erase button.

    NOTE: Hard drives actually have a bit more space than what you see after they’re formatted. That spare space comes into play whenever a sector on the drive must be mapped out…that sector is replaced by a good sector from the spare space. That way even if some sectors are mapped out, you have the same amount of space on the drive after formatting. Of course if a drive has more bad sectors than the amount of available spare space, it must be replaced.

    This erasure will take a while…perhaps several hours, depending on the size of your drive.

    5. If the erasure is successful, quit from Disk Utility to return to the original OS X Utilities window, then double-click on Restore From Time Machine Backup. Follow the prompts to restore from your external drive. If the erasure is not successful, skip this step and move on to step 6.

    6. If the erasure is not successful, the drive will have to be replaced, and the new drive will have to be formatted as a Mac drive, and OS X will have to be installed. Once that’s done, you boot into the Recovery HD from your new drive and perform Restore From Time Machine Backup as described in step 5.

    Hope that helps!

  133. Arianna Says:

    September 10th, 2014 at 11:19 pm

    Hi I have a 3 year old MacBook Pro with mavericks iOS. I did the fsck thing and my final message was “the volume Macintosh HD could not be verified completely.” I have no idea what to do and I have two exams I need to study for tomorrow. Is there any hope I can fix this myself? How do I get out of this screen? What can I do to fix my computer? And how much is it going to cost me?

  134. darryl Says:

    September 11th, 2014 at 2:11 am

    First, to get out of the current FSCK screen, you can do two things. If you see the root# prompt, either type reboot or shutdown, then the Return key. That will either restart your Mac (reboot) or shut it off (shutdown).

    I’m concerned that if the FSCK procedure couldn’t verify your hard disk, there may be more problems than FSCK can fix. In cases like that, you’d have to turn to a third party utility like Disk Warrior or TechTool Pro, or take your Mac to your neared authorized Apple repair center or your closes Apple Store.

    Disk Warrior 4 is available at http://www.alsoft.com/diskwarrior/ for $99.95.

    TechTool Pro is available from https://www.micromat.com/products/techtool-pro for $99.99.

    Your nearest Apple Store is at Aventura Mall.

    Wish I could be of more help.

  135. Toni Says:

    September 16th, 2014 at 10:45 am

    When my mac starts its stays on a white screen with a grey apple logo a loading sign is under and a grey bar is filling up halfway through my computer just shuts Down please help

  136. darryl Says:

    September 16th, 2014 at 5:56 pm

    Based on what you said, your computer is either booting into firmware update mode, or into safe mode. Both can display the status bar filling up below the gray apple during booting. Try these instructions for fixing the problem.

    1. Restart your Mac, and as soon as you hear the startup chime begin holding down the Option key on the keyboard. You should see a gray screen with a big icon for each bootable drive connected to your computer. Even if you have only your internal drive connected, you’ll see that drive plus another called Recovery HD. Double-click on Recovery HD to boot your Mac from that drive.

    NOTE: Recovery HD is actually a separate, bootable partition on your internal drive that contains Apple utilities that can restore your main partition from a Time Machine backup, reinstall OS X, or run Disk Utility on your main partition as though you’re booted from a separate hard drive.

    2. Double-click on Disk Utility in the OS X Utilities window to launch Disk Utility.

    3. In the Disk Utility window, click on the actual name of your hard drive in the column at the left side, then click the Repair Disk button at the lower right corner of the window. Depending on the size of your drive, this will take a few minutes.

    4. When the disk repair is complete, and which your hard drive’s name still selected, click on the Repair Disk Permissions button. This will also take a few minutes.

    5. Restart your Mac normally and see if it boots up to the desktop. If not, repeat step 1 to boot from the Recovery Drive, and this time click on Reinstall Mac OS X in the OS X Utilities window, and follow the prompts to reinstall OS X on your hard drive. Your data will not be disturbed…only components of OS X itself will be replaced with new, clean copies. Once that’s done, you should be able to boot your Mac normally.

    Let me know if that doesn’t work…good luck!!

  137. Stalo Nic Says:

    September 17th, 2014 at 7:24 pm

    Hi Darryl, I start my i-mac while pushing the alt key to boot from the OS X install dvd. I only get the option to go using Macintosh HD. I press on it and it eventually goes to the blue screen..what can I do?! Please help! I’m panicking here!

  138. Jessicah Says:

    September 18th, 2014 at 4:10 am

    Hello there Darryl,

    Ever since I lost a game of chicken with my Macbook (your system has no memory left so you should shut down applications, etc., then it froze, so I forced shutdown), it’s has been booting to a flickering blue screen with a cursor and nothing else (all the other loading screens prior to it go through fine). I’ve been trying to boot it into Safe Mode, but when I get to the login screen and enter my password, it totally acts as if it’s going to take me in, vanishing to load up, but after a few hopeful moments it bumps me back out to the login dialogue box.

    It recognizes my password as correct (because I tried entering incorrect ones and the dialogue box does the ‘this is wrong’ shake)–it just won’t get me IN. :( Is there a reason for this? I can boot into SUM, and have transferred all my files over as well as repaired the disk in Disk Utility from my mom’s computer in Targeted Mode, as well as freed over 90 gigs of space on it–but I really need to have the laptop itself work if possible.

    I tried fooling around with chmod stuff in SUM, (getting ‘your system is ok’ results), resetting the PRAM, taking out the battery. Kind of just futzing around in general without really understanding what it is I’m doing. :/ I feel like it’s something fixable but I don’t know near enough about computers to know how to go about fixing it. Which is where people like you come in. XD Any insight would be greatly appreciated.

    I’ve been working from my Windows partition for almost a year now…and then screwed *that* up trying to fix some stupid USB thing that was causing 100% CPU usage, so now I’m trying to go back to fixing the Mac side. *sigh* If I can’t figure something out this thing will turn into one big paperweight. *tears*

    Life sucks when you’re broke

  139. darryl Says:

    September 18th, 2014 at 5:54 pm

    Hi, Jessica. Based on your description, I’m not sure whether the database that OS X maintains for user accounts (including passwords) is damaged, whether OS X itself is damaged, or whether your Desktop folder is missing. Any of those things could cause the problems you’re describing.

    So, for example, assuming that OS X is OK, and the database of user accounts is OK, and you log in with the correct password, if the Desktop folder (which is normally within your home folder) is missing, OS X can’t go to your desktop because the Desktop folder is missing.

    Or, if the user account database is corrupt, you could enter any password at all…even the one you know is correct…but it still might not match the corrupt password or user name stored in the damaged file, and wouldn’t allow you to log in.

    And of course, if part of OS X itself is damaged, it may not be processing your login request correctly.

    The very first thing to do is to boot your Mac from a different hard drive and make sure you have an up to date backup of the entire disk…preferably to an external hard drive. You can use Time Machine, or a third party disk cloning program like Carbon Copy Cloner (my favorite) or SuperDuper!.

    Next, presuming you’re running OS X 10.7 or later, reboot your Mac from the Recovery HD. To do that, start up your Mac, and as soon as you hear the startup tone press and hold the Option key on the keyboard. You’ll see a gray screen with big icons for every bootable disk connected to your Mac, including one called Recovery HD. (Recovery HD is actually a partition on your internal hard drive, not a separate disk, but you can boot from it to fix problems in your main drive.) Double-click on Recovery HD to boot from it.

    When you get to the desktop, you’ll see a window that offers choices to Restore from a Time Machine Backup, Reinstall OS X, Get Help, or launch Disk Utility. Ignore those choices. Instead, click Terminal under the Utilities menu. In the terminal window, enter the command resetpassword, then click the Return button.

    A new Reset Password window opens. Make sure your internal hard disk is selected in the top pane of the window, then select your user account from the menu below. Make note of the user name, because the way it appears in that menu is exactly the way it should be entered with you log in.

    Now enter the password you want to use twice in the spaces below, and an optional hint. Finally, click the Reset button at the lower left corner. This will overwrite your login information in the user account database, and hopefully restore your ability to log in.

    Now reboot in Safe mode and attempt to log in. And if that works, do a HAPPY DANCE! If not, let me know.

  140. Besnik Says:

    October 1st, 2014 at 11:48 pm

    Hello Darryl,
    I haven’t seen some one like you replying to each message for a while.. good job. Keep it up :)

    Now, I have a MacBook Air.. I don’t really know which year but for sure I know that I have Mac OS X 10.6.8.

    Now about a week ago, I uploaded everything I had on my Windows PC as a restore a safe disk to my Mac, which I don’t use so often, all my family pictures and everything and today when I started my Mac, I just see the Apple Logo, and the thing down spinning and spinning.

    Note.: I believe that I have a lot of available space, since I used maybe only 20-30GB of my 160GB disk
    Now, I will tell you what I did so far and what I tried.:

    1. Command + S
    everything seems fine except this line which looks like an error
    BSD root: disk0s2, major 14, minor 2

    Now, I write /sbin/fsck -fy and I get message “The volume Macintosh HD appears to be OK.

    After this I write “fsck_hfs -y -rc -d /dev/disk0s2 and I get this message:
    Ivalid volume file count (it should be 284023 instead of 284017)
    Invalid Volume free block count (It should be 7734809 instead of 7734815)
    Volume header needs minor repair (2,0)
    Than in the end I receive the message The Volume Macintosh HD was repaired successfully.

    Than I do this step again, and again, and again, I get the same message.
    Note** I receive the error in volume and free blocks only first time, the other times i just get the message that the file system was modified and hd was repaired successful.

    2. I have tried to hold the shift on startup but that makes it load for 5-10 seconds the loading banner below, than it goes away.

    3. I tried the Command+Option+P+R and hold it until I receive 4 beeps, that just made my screen brighter :) nothing else.

    4. I tried another command which I don’t remember right now, but there I saw an error “disk0s2 1/0″ and it was repeating and repeating…

    So, what do you think? What should I do? I would give a lot an whatever it takes just to recover some family pictures I had stored in that disk.. and it seems I don’t have any mayor problem with disk like I can see with other people having..

    So what is your suggestion, what should I do?
    And thank you a lot in advance :)
    Besnik

  141. josh Says:

    October 2nd, 2014 at 2:58 am

    I’ve read some of the posts above, but have not found a solution to my problem. I did /sbin/fsck -fy in single user mode, and got a success message, and then booted in safe mode. I logged in, and the default 10.6.8 snow leopard background appeared. However, nothing else does. There is no dock, no finder bar at the top, and no icons on the screen. I’ve tried multiple times and this keeps happening. The mouse does appear and I am able to move it, but I can’t get it to properly boot up.

  142. Kostas Says:

    October 3rd, 2014 at 2:36 pm

    Hi Darryl!

    Thanks for spreading the knowledge and all the info like this! Very helpful and really appreciated.

    I followed your instructions, and my disk appears to be ok after one modification. I did it again and it appeared to be ok, without getting the modification message. It took the computer around 2 hours for the two checks.

    Then typed reboot and it went again on an endless spinning below the apple logo. So i tried safe mode. After the chimes tone i pressed shift and waited for a long time. While i could see the logo no spinning wheel appeared. All of a sudden the screen went black and i heard the chimes sound again. I tried once more the safe mode but the same thing happened again. Then i restarted and after the tone i pressed cmd and r but it went on endless spinning again. Same exact thing when i pressed the option key after the tone. What do you think?

    I’m using imac 10.6 bought at 2010, with a wireless keyboard. I have unpluged all the devices from the ports. could it be my timming? I’m pressing the buttons 1second after the tone and keep them pressed for 3 to 6 minutes before i stop.

    It all started yesterday when it froze and could not relaunch finder. So i decided to restart and the endless spinning started.

    Is it time to panic? Is there a chance to back up data even now? What can i try next? I wish i could visit you but i’m uk based.

    Thanks for your time!

  143. darryl Says:

    October 4th, 2014 at 4:28 pm

    To access Safe Mode, just press the Shift key…not Command-R. Since you’re using a wireless keyboard, the timing can be a bit finicky…make sure you don’t press the Shift key until after you’ve heard the startup tone…that’s when your computer makes a wireless connection to the keyboard. With OS X 10.6 and later, you shouldn’t have to hold down the key for so much time. What you should see on screen is the gray apple, and within a short time after that appears, a progress bar at the bottom of the screen below the gray apple. As soon as the progress bar appears, you can release the Shift key.

    If the progress bar never appears, try doing it over again, but this time way a second longer before pressing the Shift key…or, better yet, borrow a USB keyboard and use it. With a USB keyboard, you can press and hold the Shift key at any time.

    With wireless keyboards, the Mac senses when keys are depressed, and when they’re released…not whether they’re actually held down or not. If you happen to press the key before the Mac actually makes its wireless connection to the keyboard, the Mac misses the actual key press…so it simply accepts the current state of the keyboard as the “default” state, where all the keys are unpressed. That’s why timing is a bit tricky.

    Even after all the years I’ve been servicing Macs, I sometimes have to try procedures that require pressed keys a few times before getting the timing right with wireless keyboards…a lot depends on the speed of your particular computer (how fast it’s able to establish its connection to your wireless keyboard). Don’t worry if you have to try a few times…

    If the Safe Boot doesn’t resolve the booting issue, your next step would be to try booting from an external USB or FireWire hard drive with OS X installed. If you have the OS X 10.6 install DVD, you can use that to install OS X on the external, then boot from that drive. There’s a very good chance that your internal drive will appear on the desktop, and you can back up your data. You can also use a third party disk repair utility like Disk Warrior or TechTool Pro to repair your internal drive. They are much deeper repair utilities than the built-in FSCK routine.

    Good luck!!

  144. darryl Says:

    October 4th, 2014 at 4:45 pm

    Something you said leads me to believe your internal drive may be failing. You said, “4. I tried another command which I don’t remember right now, but there I saw an error “disk0s2 1/0″ and it was repeating and repeating…” The 1/0 error is more likely an I/O error…input/output. Those errors indicate problems reading from (or writing to) the disk, and are often an indication that the disk either has places on its surface that are not storing the information written reliably…so it can’t be read back accurately.

    I would use a third party utility like Disk Warrior to attempt to repair the disk. The beautiful thing about Disk Warrior is that it creates an optimized version of the disk’s directly in the RAM of your computer…without ever writing anything on the drive. At the end of the scan, you can click the Preview button, which displays a virtual copy of your disk on the desktop as it would be if you replaced the directory with the optimized version. Since I suspect the disk itself may be failing, I’d back up the virtual disk to an external USB or FireWire disk…that way you know you have your files.

    Once you’ve got your files, I’d erase your internal hard disk with Disk Utility, but set the Security setting to write zeros to the entire disk. When you write zeros, Disk Utility also checks every data block on the surface of the disk for reliability, and maps out any that aren’t reliable. If the erase it successful, it should eliminate the I/O error. If the erase fails, it’s time to replace the drive itself.

  145. darryl Says:

    October 4th, 2014 at 4:47 pm

    I would try reinstalling OS X at this point. It sounds as though there’s an issue with the Finder, which is the application in OS X responsible for creating the desktop screen. If the Finder isn’t working properly, you’d see precisely the symptom you are…the Dock can’t load, the menu bar can’t appear at the top of the screen…and you can’t really do anything because it is from the desktop screen that you access everything.

    Good luck!!

  146. Karin Says:

    October 9th, 2014 at 7:02 am

    Hi Darryl. I tried safe mode and disk utility but nothing boots so I tried single mode with command s and it goes to the black screen with the white letters. The problem is the screen says

    single user mode: exit status 1 (multiply times,) then singleuserboot–fsck not done
    Root device is mounted read-only

    If you want to make modifications to files:
    /sbin/fsck/ -fy
    /sbin/mount -uw /

    If you wish to boot system:
    exit

    Then it repeats and keeps twitching and not allowing me to finish typing the fsck part. With every twitch of the screen it erases my type. Twitches every second

    Any ideas on what the problem is and how to fix this?

  147. darryl Says:

    October 10th, 2014 at 12:26 am

    I need a little more information, Karin. What version of OS X are you running? If its OS X 10.7 or later, did you boot into the Recovery HD and run Disk Utility from there? (Versions earlier than 10.7 don’t have a Recovery HD, so you’d have to use an external drive with OS X installed.)

    The error “exit status 1″ is a general error. There are exit status errors with other numbers that are specific, and any error that doesn’t fit one of those specific errors displays exit status 1.

    If I had your computer here in my office, I’d first try booting it from an external hard drive…to see whether your internal drive pops up on the desktop. If so, I’d immediately clone your internet drive to an external so that I know I have all your data. Then, if you’re running OS X 10.7 or later, I’d boot using the Recovery HD and reinstall OS X. Doing that wouldn’t affect your data…it would only replace the existing parts of OS X itself with cleanly installed versions…which might make it possible to boot.

    If that failed, my next step would be to completely erase your hard disk, do a clean installation of OS X, then use Migration Assistant to restore your applications and data from the backup. With that done, you computer should boot normally. Your desktop should look just as it did before this problem. All your files, applications, email…everything…should be the same as it was.

    I hope this helps, Karin. Contact us if you need more help. Good luck!!

  148. charlie Says:

    October 12th, 2014 at 5:32 am

    Hi, I was using my macbook pro and all of the sudden the screen blacks out but my music was still playing. I turned it off and on again, it gets stuck in a grey screen after the apple logo shows up. I tried the single user mode and everything is okay, I rebooted it and it’s the same thing. I can’t get into safe boot, the progress bar gets to 1/3 of it and then a blue screen shows up. Is there any way I can still save my macbook without erasing the files inside? Thank you!!

  149. Bret Says:

    October 21st, 2014 at 12:50 am

    Hi Darryl. Thank you for all your helpful advice online. My iMac (2007 Aluminum, Maverick OS)refused to boot a few days ago. I just moved my home, and I didn’t have enough time to back up my data for the past two weeks (shame on me!). Now I just want to retrieve my data.

    Following your advice and those elsewhere, I’ve done the following in order:

    1) Safe Mode: still hangs. After I tried the “Verbose Safe Mode”, it splits out I/O Error.

    2) Recovery Mode: is able to select the recovery partition at startup, but still hangs.

    3) Installation DVD: got to the disk utility page, but it says the disk has S.M.A.R.T Failure. Unable to do anything with it. Launched the Bash Shell, but unable to type anything in it (could it be because of my bluetooth keyboard?).

    4) Prosoft Engineering Disk Rescue Bootable USB: tried both Quick Scan and Deep Scan (it was able to detect my HD), but it quickly says can’t find any files.

    5) Single-Command Boot: (a) “/sbin/fsck/ -fy” says everything is fine. But when I try “fsck_hfs -y -rc -d /dev/disk0s2″, it returns disk full error, although my disk is not full. (b) “/sbin/mount -uw /” returns I/O Error.

    What’s your assessment of my hard drive? I just want some of my data back. Do you think the following is still worth doing? I have to pay more money to try these:

    1) Disk Warrior Bootable DVD: With Prosoft Engineering Data Rescue unable to recover anything at all, is Disk Warrior worth a try?

    2) Target Mode Boot: Same as above, with Data Rescue failing to recover anything, would Target-Mode-Boot change anything?

    3) USB-SATA-Adapter: Open my iMac, take out the hard drive, mount it on the USB adapter and try it on my other mac. Is this worth trying?

    What else would you recommend? Again, thank you for all the help!

  150. darryl Says:

    October 21st, 2014 at 9:16 pm

    If I had your MacBook here, this is what I’d do:

    1. Start up your MacBook from an external bootable drive. It’s likely that your internal disk would show up as a mounted drive, and could be backed up to another external drive.

    2. Erase your internal drive, install a clean copy of OS X, then use Migration Assistant to copy all your programs and files from the backup to the internal drive. In the end, your Mac should boot up, and look and feel just as it did before this problem.

    Alternate thing to do:

    Since you say your internal drive passed the FSCK test when you booted in Single User Mode, you could simply reinstall OS X on your internal drive.

    If you have OS X 10.6.8 or earlier, you’d have to boot your MacBook from the installation DVD to perform the installation.

    If you have OS X 10.7 or later, boot up while holding down the Option key on your keyboard. Your screen would display a large icon for each bootable disk connected to it, including one called Recovery or Recovery HD. Select the Recovery disk to boot from. When you get to the desktop, you’d see a window offering you four choices, including Reinstall OS X. Choose that option, and follow the prompts to reinstall OS X. This would not change any of your own applications or files…it would just replace the existing (likely damaged) OS X with a clean copy. You should be able to boot normally after that.

    Good luck!!

  151. darryl Says:

    October 21st, 2014 at 9:34 pm

    Based on the I/O error you mentioned, I’m concerned that your internal drive is failing. I/O stands for Input/Output…meaning read and write. If the drive is having errors reading and writing, your data is certainly at risk. The good news is that your computer is recognizing the disk, which means that the controller card is talking to your logic board.

    I am concerned that if your drive is recognized by the logic board, and yet Data Rescue isn’t able to find any recoverable files on the disk, the disk is mechanically damaged. Either the disk is not spinning at the correct speed, which makes it impossible to read and write files, or the positioning mechanism that moves the read/write heads to where they need to be on the disk surface is not working, or the heads are damaged themselves.

    In this case, I would not try anything else myself, because continuing to try to use the drive may be doing more mechanical damage. If it’s essential that the data be recovered, send the drive to a commercial drive recovery company. They have the necessary clean-room facilities to disassemble the drive, replace parts, or even transplant the actual disk where your files are stored into another working mechanism of the same model.

    Based on your IP address, it appears you are in Hong Kong, and unfortunately I don’t personally know drive recovery companies there. However a quick Google search of “drive recovery in hong kong” brought up a list, including one of the major players in the field. Kroll OnTrack Data Recovery, +852 2586 5805, http://www.ontrackdatarecovery.com.hk

    My very best wishes!

  152. DeVon Says:

    October 24th, 2014 at 12:29 am

    Just wanted to thank you for you expertise. although I had not sent you an email I read through some of the advise you gave to people asking questions pertain to the blue screen. Well the shift key worked for me. Thank you very much for taking the time to do what you do.

    wish you all the best
    Kind regards
    DeVon

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