I have a client running SBS 2003. Backups have worked fine for ages, but for the past couple of weeks have been failing on Exchange.
The error in the backup log is:-
Backup of "MYSERVER\Microsoft Information Store\First Storage Group"
Backup set #3 on media #1
Backup description: "SBS Backup created on 06/09/2011 at 20:30"
Media name: "Small Business Server Backup (02).bkf created 06/09/2011 at 20:30"
Backup Type: Normal
Backup started on 07/09/2011 at 03:06.
Error: The device reported an error on a request to write data to media.
Error reported: Invalid command.
There may be a hardware or media problem.
Please check the system event log for relevant failures.
The operation was ended.
Backup completed on 07/09/2011 at 03:48.
Time: 41 minutes and 26 seconds
Error: MYSERVER\Microsoft Information Store\First Storage Group is not a valid drive, or you do not have access.
I have run an integrity check on the stores, and they seem OK.
The backup runs to an NAS box. The NAS box has more than enough free space for this.
Everything else backs up OK, I just can't figure out why this fails.