This is a large environment with several servers, both 2003 and 2010 servers. And there was one mailbox that was on one of the 2003 servers - but had some errors (no properties set on server) - so we ran Exchange Tasks and deleted mailbox - just to discover that the mailbox had been moved to 2010 - and the "thing" on 2003 is some orphaned thing (which stops us from decomissioning the server)
But the thing is that now the user object have no exchange tasks on the 2003 server in ADUC, and the mailbox is lost from 2010 server.
and ---- it is not present in disconnected mailboxes as well (!!!) --- even though we have 200 days retention period.
is this an AD or exchange issue now? and how to restore exchange features on user object ??