I'm running exchange 2k post sp3 rollup. when i try to do a search on certain users in message tracking, i get "one or more entries in the Recipients field are invalid and will not be used in the search. Each entry must be a valid email address or user" For other users it works. there is nothing different about this user- enabled account,not hidden from the gal,etc. This is a valid user in my domain. She has a mailbox/email on an exchange server in the org. i am running this as domain admin with full exchange admin rights. any ideas? thanks alot.