If you want to reuse a CD-RW disc, you must first erase the existing information on it. Before you erase the disk, make a copy of any files you don’t want to erase.
The erase procedure for MacOS Sierra and later is different from that for El Capital and earlier, so choose the right procedure for the version of MacOS you’re using.
Sierra and later
Insert the disk. When it appears on the desktop, right-click (or Control-click) on the disk’s icon, and choose Erase disk in the contextual menu that appears. The disk will be erased.
El Capitan and earlier
Erasing, reformatting, or preparing a disk for burning permanently deletes all of the disk’s contents.
- Insert the disc.
- Open Disk Utility (Applications/Utilities).
- Click the Erase tab.
- Select the disc from the list of drives on the left. Make sure not to select the hard disk.
- Click Erase.
CD-RW discs may deteriorate after being erased many times. Check the specifications for the disc to find out its expected life.
Try doing it this way, without using Disk Utility. Most optical disk functions have been removed from Disk Utility starting with OS X Sierra.
In the Finder, right-click (or Control-click) on the CD/DVD-RW icon on the desktop. Select the option to erase the disk in the contextual menu.
This worked! Thank you!