Backup-to-Disk folders going offline and BackupExec creating @@@@@@@@.bkf files.

[Savvy_Support]

My Backup-to-Disk folders keep going offline.  And when I go to investigate, I notice files name @@@@@@@@.bkf files have been created.  Any one else get these and does anyone know of a fix?

[Ken_Putnam]

See http://seer.entsupport.symantec.com/docs/292874.htm

The alert "The Backup-to-Disk device is offline" appears while performing a backup to a Backup to Disk folder using Symantec Backup Exec 12.0 for Windows Servers

[Ric_Turner]

I too am getting the same error. I am running v12.5 rev 2213. However, I have checked the KB above and my "Allocate the maximum size..." box is not checked. The backup to disk folder is on a local drive (D:\) so cannot be losing connection to it over the network. Originally I didn't have the "mnt" folder or the "VMBackup" (my backup-to-disk folder) shared. So I shared them and re-created the Backup-to-disk folder. This seemed to work for a (very) short while but is now happening again so I guess this was a red herring. Any ideas?