Receiving Duplicate Emails

If you are receiving duplicate emails there are a few items you should check -

• Sometimes there are rules set in Outlook those can cause duplicate mails.
• Also check if you have set aliases in Outlook for same email account.
• Is it a POP or IMAP account ? In IMAP account, if you have set option for retrieve new emails automatically upon startup, then it will cause duplicate mails. If this is the case, then you can uncheck the option to connect to mailboxes.
• Sometimes "Leave a copy of the messages on the server" can cause such issues. This option should be disabled.

Please refer to this link for further information. http://www.howto-outlook.com/faq/duplicates.htm