I have noticed that on a number of clients running WIN2K3 SP1 that are being backed up using VSS, there are files being created in the hidden folder called 'system volume information' on the drive being backed up. These seem to be cache files and coincide when a snapshot is being created, they do not seem to be clearing once the backup has completed like the .VSP cache files created by VSP and are occupying space going into hundreds of gigabytes. The vssadmin command available in WIN2K3 cannot clear these files since it does not recognise they exist but it does show them occupying space on the disk in gigabytes, it is almost as if they are orphaned files.

Has anyone else come across this problem, since it also seems to be evident on a Windows SAN media server. I have been told antivirus software can stop the cache files from being deleted.

I have also set antivirus exclusions on *.VSP, bpfis.exe, smm.exe as per tech note.
Is it possible the system volume information folder needs to be added as exclusion to the list of files to be backed up and the antivirus exclusions list.

Can the existing shadow copy files in this folder be causing an unexpected error state.
The Netbackup configuration consists of all Windows 2003 servers running SP1.
The Master server is running Netbackup 6.0 Enterprise with MP4.
The 2 Media Servers + 4 SAN Media Servers are MP4 as well with access to 4 robotic libraries.

Any ideas or recommendations on how I can resolve this issue would be helpful since the problem is getting worse with every backup eating into the free disk space.