I have come across a rather odd user query. An external email was sent addressed to person A as joe.adams@abc.org.uk (this was person A's correct SMTP address) but actually arrived in person B's mailbox. I checked in Xchg Admin on both mailboxes and there are no alternate recipient rules set up. I asked person A if he has any rules set up in Outlook to move inbox messages to person B and the answer is "no". I have asked person A to double check his Outlook rules - in the meantime, does anyone have any theories as to why this may have happened?