Previously Trend Micro's ScanMail was installed on this cluster server. Trend Micro allows control of scanning of individual mail stores, and these registry entries control that individual store scanning function. When ScanMail is removed, registry entries are left behind, which directs all information from VSAPI to the Trend scanner, which no longer exists on the system.
Remove Trend registry keys and restart Microsoft Exchange Information Store. Perform the following steps on each server in the cluster:
1. Remove the following registry keys.
WARNING: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to back up the Windows registry for instructions.