Backup exec 2012 on Hyper V host - FilterManager event 3
We have Backup Exec 2012 SBE running on a Windows Server 2008 R2 SP1 host which has the Hyper-V role enabled and 2 W2k8 VMs. All fully patched.
After backing up virtual machines we are seeing an error message:-
04:24:07 Error FilterManager 3 Filter Manager failed to attach to volume '\Device\Harddisk2\DR23'. This volume will be unavailable for filtering until a reboot. The final status was 0xc03a001c.
This error repeats 3 times in total.
It always coincides with a backup ending:-
Start time : 29 October 2012 04:10:46
End time : 29 October 2012 04:24:33
After each backup, the number in \Device\Harddisk2\DRxx increases by 1.
And, I see increasing numbers of entries in the registry under HKLM\SYSTEM\CurrentControlSet\Enum\STORAGE\VolumeSnapshot
It seems that snapshots are created and recorded in the registry but not deleted from there when finished with.
In the past there was a serious problem where the registry increased in size dramatically (KB982210) but this is not happening here.
As far as I can see the backups are working successfully.
But, what causes FilterManager error 3? And, how can I resolve it?
Is it an error caused by Backup Exec?
Thanks in advance