Hi Steve, thanks for you reply.
I have searched the Event Viewer as you have suggested but have found no entries in the Application or System logs for VolSnap or VSS during the times of the job (screenshot attached - unfortunately I seem to only be able to upload one screenshot). Other jobs backing up from the same volume using VSS are having no problems so I would think it doubtful VSS is the cause.
I have run the job again and this time the error is different: 0x000fe36 - Corrupt data encountered.
Again, I must reiterate that we are as certain as we can be that there is no corrupt data in this volume. Users accessing this data on a daily basis have reported no problems and the data is accessible through Windows Explorer and the Backup Exec selection window in the job definition.
All evidence so far is pointing to Backup Exec I'm afraid.