We came across an interesting issue with one of our customers which we have provided a work around for, and I thought there may well be others affected.
The customer runs Windows XP, Windows Vista running Microsoft Office 2003 and Office 2007 and have the forefront client installed.
The customer was having issues with Word and Excel files becoming corrupt with new and existing documents.
To cut a long story short we received some advice from the Forefront team to alter the registry with the settings listed below. This has now resolved their issue.
Forefront Reg update
We will be providing this fix in the next roll up slated for Forefront.