My VCB backup failed because the VM couldn't be snapped. I looked at it in VC and sure enough, "snapshot" is greyed out in the context menu. The other 21 VM's are fine.
What would make snapshotting unavailable on a VM?
I started the VSS service, restarted the server and check the vm permissions. Still got the problem. Of course Snapshot manager is unavailable as well so I can't check for pre-existing snaps.
Thanks for any help you can offer!