I have a problem with BackupExec SBS 8.6 running on Windows SBS 2000. We
installed BackupExec in 2001 and apart from a few teething problems
everything worked fine until November this year.

When I come in in the morning the backup is still running (9pm start - 12
hours there have been occasions where it's taken 58 hours over a weekend).
I have to cancel the backup. Checking the job log reveals the following
error message
Media mount failed.
User cancelled a Physical Volume Library operation.

Backup completed on 11/12/2003 at 09:04:03 .
Backed up 130126 files in 4366 directories.
1 file was in use
Processed 8,604,601,827 bytes in 3 hours, 8 minutes, and 46 seconds.
Throughput rate: 43.5 MB/min
We have 5 backup sets and BEX seems to have problems on the 4th set
(partition d: - all the companies data files). The 5th set is
\\W2KServer\System ?State. Checking the tape inventory reveals that a
random file seems to be the last one backed up (sometimes in D:\User Shared
Folder, mainly the D:\url cache\dir1.cdat). To protect the organisation I
have been running a separate immediate backup job to keep a copy of the
critical files which work with no problems. It doesn't seem to matter which
tape I use for the scheduled or immediate backup so I assume that the tapes
are OK. By running an immediate backup rules out a faulty drive.

Has anyone any ideas as to where I can look for a solution to this problem?