RMAD failed backing up a server with the error : "Unable to execute request (122). Unable to query information for the file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy869\Boot\. The system cannot find the path specified."
On windows events we get the error code "0x80004005. Error text : Unable to execute request (122)." ( see attached )
This happen in a scheduled task so other task could be using the ".dit" file ( or any other file in use ) from the DC.
Change the schedule for the RMAD backup schedule task to not running it with other tasks.
If changing the schedule does not resolve the issue, reboot both the RMAD server and the DC.