This is a know issue with Terminal Services and manual disk fail overs. I would lose drive letters during fail over when TS'ed into the nodes. Microsoft solution was to log out and log back in.
The error can occur when you use the CLUSTER /MOVE command to manually move a group. To resolve this issue, specify the /wait switch with a value that is long enough for the group to move succesfully. See ME248408 and the link to event id 1003 from source Shadow_Session.
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