We recently had our 6 year old HP 1/8 G2 Autoloader (LTO3) fail. As it wasn't under warranty I elected to just replace it with the same model but with an LTO4 drive.
Installation was easy, Backup Exec seemed happy, but when backups ran they would randomly hang (initially doing System State backups, but once I removed that they hung elsewhere somewhat randomly).
Cancelling the backup would take forever (I normally just gave up and restarted the BE services) - when the cancellation finally completes, a SCSI error would appear in the event log. If I let the backup hang for long enough it would sometimes fail, with an error writing to the tape drive.
I did lots of test using HP Tape Tools, all came back fine (initially I got a cable error, so I replaced the cables and terminator which made that go away).
Symantec say that the problem is the tape drive, as there are SCSI errors in the event logs.
Between the old device failing and the new one arriving I used a stand alone LTO3 drive, which worked fine with all the same hardware.
Subsequently I have updated HP SCSI drivers and applied all hotfixes and patches to BE, as well as upgrading the firmware on the HP autoloader (the drive itself was already up to date).
Has anyone got any suggestions? HP seem like the might be willing to send me a replacement device, but if they decide the problem is BE I'll be stuck between HP and Symantec.