When I attempt to rename a machine, I get the above error?
The machine was a duplicate, and I have deleted the incorrect entries for the machine.
I now want to rename the machine, to get rid of the x0001 addition at the end...?
Machine object is locked and in use. Make sure no other instance of EEM is having this object open.
In the worst case, restart database service (restart should be a part of periodic maintenance process).
Use EEM Best Practices document to minimize this type of transient errors.