Have you shared out a 2nd system’s hard disk drive or at least a sub-folder as a user defined share to see if you get the same issue backing up to it over the network? Does all BESR clients fail backing up to this NAS appliance? Can large files (i.e. over a GB) be zipped to a file where the destination is this NAS device successfully? Are there any firmware or driver updates that has not been applied yet to the NAS device?

Backing up to a standard computer (Win XP via a share) works fine.

I've previously used the NAS over 2-3 years backing up 46Gb backups (single file) successfully via Windows Backup from our old Win2K server, so I know the NAS can handle large files (in fact, it does do the grunt of the BESR backup, just cannot finalise it)

I'll check for firmware/driver updates for the NAS but I don't think any are available (its a Maxtor Touch II Ethernet drive)

Thanks David.

Please check the windows application event viewer for errors around the time of the backups for Backup Exec System Recovery and post them.