Microsoft Information Store\First Storage Group Database was not found, or could not be accessed."

A Backup Exec 11d or 12.0 Exchange Information Store (IS) backup to a Backup-to-Disk Folder fails with the error: "Backup- \\Exchange\Microsoft Information Store\First Storage Group Database was not found, or could not be accessed."

http://seer.entsupport.symantec.com/docs/290493.htm

Resolution: exclude the backup folder from the local antivirus server