I solved this one once by accidentally trying to delete the folder
containing the one I'd been trying to kill, after changing permissions
and ownerships of the offender without much success. I even tried to
kill the stuck one using Windows. Nothing worked.
If the stuck one is not in a higher folder, maybe putting it inside
one would work? I know this raises inheritance issues but it *might*
work. Maybe. If you fiddle enough with "chown".
There's a fairly recent "Solved" thread about what happened in one of
the Maccy groups.
By "fairly recent" I mean sometime this year or last.
Mel C., do you want me to try to find the message-ID?