A user in my company is seeing duplicate emails in their Outlook Inbox. I checked the Message-ID and they were the same, so these looks like the same message. Checked OWA, and they were in there as well. All emails are from internal senders anyway so whatever happens the problem is on our side!
Not user on where or what the problem could be? AV on the user's PC looks ok, can't see anything strange happening and we haven't made any changes to Exchange (2007) recently