On a Server 2008 R2 Standard machine we were having issues with backup drives and so removed them all and re-added. The first one worked fine and we were able to get a successful backup, so we then added the remaining two drives. On clicking Finish on the wizard, we then observed that a data drive disappeared, and on checking Disk Management we could see that the whole volume had been renamed using the Windows Server Backup format and formatted! We are 100% certain that that drive wasn't selected as a backup destination, and on re-opening WSB and checking the destinations in use it wasn't listed, but the two ones we did mean to add were.
This is obviously very worrying as we're now not sure if we'll ever be able to safely add or remove backup destinations on this or other machines in the future.
Has anyone else experienced this? Is there anything we can check to try and determine why this happened?