ISA server Configuration for OWA 12
If you are using Internet Security and Acceleration Server (ISA ) between users and Outlook Web Access servers, the ISA Server rule called "Verify Normalization" needs to be turned off to enable Outlook Web Access document access functionality. Exchange Server "12" sends double-encoded spaces in document and folder names that contain spaces, which is a behavior that is blocked by ISA Server. DO a search in ISA server help for information on how to turn off Verify Normalization