How to Clear the WPF Font Cache


You may experience an issue with the Test Studio user interface. A corrupt WPF font cache may cause the drop-down menus to not expand and their values unable to be selected.



Clear the WPF font cache.

  1. Start > Control Panel > Administrative Tools > Services (or type services.msc from the Run command box).
  2. Stop the Windows Presentation Foundation Font Cache service.
  3. Delete the cache file: FontCache3.0.0.0.dat
    • WinXP: C:\Documents and Settings\LocalService\Local Settings\Application Data
    • Vista/Win7: C:\Windows\ServiceProfiles\LocalService\AppData\Local
  4. Restart the service or the machine if needed.


Please see these threads for more information: