The form cache file FRMCACHE.DAT is not valid contact your administrator


EQ Forum Admin
Staff member

Did you get the following notification from Microsoft Outlook?

The form cache file FRMCACHE.DAT is not valid. Contact your administrator.
The fix for this error message varies depending on the source of the problem.

First, before you do anything else, try rebooting your computer. I'll explain why below.

If that does not work, if you have Microsoft Outlook 2007 or earlier try :

  • Open Outlook
  • Go to the Tools menu and select Options
  • Go to Other
  • Then Advanced
  • Then Custom Forms
  • Increase the storage allocation
  • Clear the cache
I am using Outlook 2010 and believe the problem was caused when my computer ran low on memory. The FRMCACHE.DAT error started appearing a few minutes before I started to receive a variety of errors about Windows not being able to load DLL files. A reboot did not fix the Outlook problem, but it did fix the out of memory issues. After my workstation was done rebooting I did a windows file search for FRMCACHE.DAT and moved the file to c:\Temp. After restarting Outlook and letting it recreate the file I no longer had a problem.