I had setup an external contact in exchange (Mail Contact) for a contractor (let's say Joe User, forwarding to email@example.com).
I was having the problem whereby any mail sent to Joe User from within exchange was always arriving at Joe's end with a winmail.dat attachment. Figuring this may be related to the fact that I had Joe setup as a mail contact in exchange, I removed the contact from exchange.
Now from Outlook, if I compose an email to firstname.lastname@example.org (as I would to any person not @mycompany.com) I get a delivery error, immediately, from exchange advising that the recipient 'Joe User@mycompany.com' can't be found. It's as if Exchange is trying to resolve this locally, rather than delivering it externally.
Any suggestions on how to get Exchange to 'forget I ever added this guy as a mail contact' and deliver the mail externally as it would with any other domain?