When a backup of MS Exchange is performed, the following error is logged.
CExBackup::backupService:HrESEBackupSetup: Error Number 0xc80001f9: Backup is already active.
Software: Backup Manager
Version: 5.X.X.X & up
OS: Windows Server 2003 & up
Backup Set Type: MS Exchange Server Backup
Description & Background:
This is actually an error message that is returned by the OS itself, suggesting that there was another backup already running when the Backup Manager attempted to trigger the exchange backup.
Another backup process is currently running when the Backup Manager tried to run.
Verify if another backup was indeed currently running (even another backup software). If so, wait until it is finished before attempting to run the Exchange backup.
If no other backup was running, try restarting the "Microsoft Exchange Information Store" service and then try again.