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.

Check message tracking to see if you can see the duplication taking place. If you cannot then the duplication could be taking place after delivery in the mailbox. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

I would take the user out of cached mode if he currently is. Cached mode has been observed sending duplicate emails in the past though I haven't heard about causing receiving duplicates. I would at least take this user out of cached mode and see if you can reproduce the issue; is it always coming from a particular user or sets or users etc.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

I would take the user out of cached mode if he currently is. Cached mode has been observed sending duplicate emails in the past though I haven't heard about causing receiving duplicates. I would at least take this user out of cached mode and see if you can reproduce the issue; is it always coming from a particular user or sets or users etc. Also does this user have multiple email accounts in Outlook outside of exchange ie. personal pop\imap accounts? James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi, According to your description, you should check some setting on Exchange server 2007, such as transport rule in Hub Transport server. Please refer to the following steps to check. Navigate to EMC->Hub Transport->Transport Rules, open the rules and find Actions->Step 1 and see whether you select ‘copy the message to address, Bind carbon copy (Bcc) the message to address, redirect the message to addresses, send bounce message to sender with enhanced status code’. If you select the below and setup other conditions, you may receive duplicate emails. Hope this helps. ThanksPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hi, Have you tried the below ways? And have you had any update? ThanksPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.