How to Clear the Cache on Illustrator CS5
The latest version of Adobe Illustrator is even more powerful than the previous versions, but like its predecessors it occasionally gives users problems if they are using a computer that skirts the edge of the minimum system requirements. For example, there times when you are working in Illustrator CS5 when you will find that the program will inexplicably slow down or even refuse to open properly because you have too much data stored in the font cache. Fortunately, this is easily handled.
Turn off Illustrator or any other Adobe application you have running.
Go to the folder holding the Adobe cache. You will find it in the following path:C:\Program Files\Common Files\Adobe\TypeSpt
Select the “AdobeFnt*.lst” file and delete it. Do not delete any other type of file in the folder. If you do, the program may no longer work properly.
Go to the folder holding the Windows cache. You will find it in the following path:C:\WINDOWS\system32
Select the “FNTCACHE.DAT” file and delete it. Do not delete any other type of file in the folder. If you do, the program, and perhaps the computer as a whole, may no longer work properly. When you reopen Illustrator, it will work normally.