Why Am I Getting Duplicate Emails in Outlook?

By Sean O'Rourke

Creating multiple aliases to the same inbox can result in duplicate messages from automated email newsletters.
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Working with a computer program that seems to be malfunctioning can be frustrating. This notion can be especially true with Microsoft Outlook, which many people depend on daily for emails, contacts and calendars. Often settings in Outlook that are meant to help with organizing messages, such as rules or syncing with a mobile device, duplicate email messages and provide other undesired results. Before reinstalling Outlook, inspect your rules, mobile sync options and account settings to ensure engaged settings are not duplicating your email messages.


Outlook can duplicate messages based upon rules that the user has configured to incoming email messages. For example, when multiple rules apply to a single incoming email, Outlook will duplicate the message so it will arrive in all folders and inboxes where the rule applies.

Duplicate Accounts

If you use multiple email accounts through Outlook, be sure that each account is individually unique and separate from the other accounts. If a user has set up multiple aliases for a single inbox account, it is possible they will receive multiple duplicate emails in the same inbox.

Reinstalling Outlook

If you've reinstalled Outlook on your computer, email messages, contacts and other files could be duplicated as the program repeats information that is already stored in your inbox or on your mobile device.


Duplicate emails may appear in Outlook because the user setting, "Leave Messages On the Server" may be engaged. The "Leave Messages On the Server" forces the inbox to download messages from the POP 3 server that houses a user's Outlook information. The setting may be turned off inside of the 'tools' section listed under 'accounts'.