Hi, Exchange 2003 server (active / passive 2 node cluster on Windows 2003 Server) - approx. 700 internal users. A few users occasionally receive emails sent from other internal users but not intended for them. e.g. Jane Doe sends an email to her husbands external hotmail address. John Smith - another internal member of staff who does not know Jane Doe receives a copy of the email. Email tracking on the Exchange server shows the email was sent from Jane Doe to james.doe@hotmail.com and John Smith. The email header in John Smith's inbox shows To:james.doe@hotmail.com, "Smith, John" john.smith@customerdomain.co.uk Checking Sent Items in Jane Doe's Outlook it does indeed show james.doe@hotmail.com; and John Smith on the To: address line. Jane does not know John Smith, did not enter his name in the To: line and has never emailed him directly before. Same thing has happened with John Smith receiving emails he shouldn't have had from a few different users. A couple of other users have also reported the same issue but it happens most frequently with John Smith. Saying that is is only occasionally happening (once a week on average) and the issue cannot be replicated every time. Issue only seems to happen when users are sending to an external email address. Any ideas???!!! Cheers, Anthony.

If the sender type the receiver correctly without any mistakes, I suspect the issue can occur by Outlook rules. Please temporarily disable all rules on the problematic user machine and try to reproduce the symptom. Regards, NovakPlease 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.

There are no Outlook rules on the sending users account. The problem can not be replicated every time. It happens randomly - sender could send 20 emails to the external address and only 1 or 2 may end up being incorrectly copied to the internal recipient. Also seems to happen randomly from a handful of senders, issues is the same each time. Sender is sending an email to an external address, it occasionally gets copied to john.smith@customerdomain.co.uk with his name on the To: line. Happens from several different senders - internal recipient is usually john.smith@customerdomain.co.uk although the customer thinks this may have happend wioth one or two other recipients and are trying to clarify this for me atthe moment. Anthony. MCSE NT4, MCSE 2003, MCITP Enterprise Admin 2008, MCITP Exchange 2010, MCITP Sharepoint 2010, Various MCTS, ITIL v4, CCA, and a bunch of other stuff... :)

Since the issue occurs sporadically, we can eliminate the Exchange cause. If the issue is caused by Exchange side, the message will keep sending a copy to the internal recipient. To troubleshoot the issue, please temporarily turn off firewall and antivirus program on the machine and send the test message again. If the issue persists, please send the message via OWA instead of Office Outlook to check the result. Meanwhile, please copy the Internet Headers of the problematic e-mail in John’s Inbox and post it here for research. Regards, NovakPlease 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.