When programs display text in Mac OS X, they don’t actually use the original copy of the font. Instead, Mac OS X and programs from Adobe, Microsoft, and Quark create their own copy each font and store it in a quick-access file called a font cache. Using font caches is a good idea for two reasons.

  1. Frequently accessed files are more prone to corruption than files accessed infrequently. By using a copy of your fonts, Mac OS X is protecting the originals. If the copies become damaged, you can simply delete them and Mac OS X automatically make a new copy from the original.

  2. It takes longer to access files when they’re scattered all over your hard disk than if they’re in one place. By keeping all the fonts you use in the font cache, text displays more quickly on screen.

Over time, font cache files tend to become corrupted because they’re accessed and modified so frequently. When they do, the text in any or all your programs may display odd spacing, wrong letter shapes, substituted characters, or look like garbled gibberish.

Test may look like gibberish.


When you see those symptoms, it’s time to clean your font caches. Once they’re deleted, Mac OS X and your programs will simply create clean new ones.

If you typically use FontBook (the font manager that comes with Mac OS X), Extensis Suitcase, or other font manager software that doesn’t have built-in font cache cleaning, click here for instructions about how to Clean Your Font Caches with Font Finagler.

If you use Linotype’s FontExplorer X or FontExplorer X Pro, the tools for cleaning font caches are built right into the program. Click here for instructions about how to Clean Your Font Caches with FontExplorer X.

If the text in Microsoft Entourage looks like garbled gibberish, you can clean its font caches manually. Click here for instructions about how to Clean Your Font Caches for Microsoft Entourage.