We have a server with consistently failing WBS backups. The errors given on the backup read: The backup of the volume was stopped before the backup started running. There appears to be an error with the volume shadow copy service on this server.
Trying to disable or change the settings of shadow copies on the C: drive result in the error "Failed to delete shadow copies of volume C:\. Error 0x800706ba: the RPC server is unavailable" if disabling and "failed to initialize the Settings dialog for volume C:\." (with the same error code) if trying to change settings. From what I can tell everything appears fine with the RPC service, but the volume shadow copy service doesn't really respond to any start or stop commands.
The server has been rebooted several times since the issue started with no change. I've also run the batch file to re-register all the various VSS components.