See http://www.howto-outlook.com/Downloads/clearformscache.htm for a script.
The causes of forms cache corruption vary with the Outlook version, which you didn't mention. Not all are known.

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Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> Hi
> Is it Possible to clear the Forms Cache Programmatically without
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>
> Thanks