Reasons for Duplicate Emails in Outlook & Prevention

Microsoft Outlook users have to deal with lots of emails on a daily basis because there can be several email accounts in a single application. If you are using a business account, then you have to constantly engage in rigorous email communication. There is a search feature in Outlook where you can search a definite email easily when the number of emails is too many. Sometimes, the user has to deal with a unique problem when the same email is present in the mailbox multiple time and want to find out the reasons for duplicate emails in Outlook.

The duplicate email is an innocent message that is only taking the space of some KBs. But, if the number of duplicate emails is too many, then it will create several problems.

Associated Reasons for Duplicate Emails in Outlook

  1. Replying to an email can be tricky when there is more than one email with the same message.
  2. PST file of Outlook has limited space. Duplicate items occupy the limited space unnecessary and stop new emails.
  3. Taking the backup of emails also becomes confusing as that which emails should be saved.
  4. Many businesses have to save the email due to security compliance and duplicate items make such tasks harder.

There are several reasons for duplicate emails in Outlook and you can recognize them in your Outlook environment also.

Multiple accounts in Outlook

Outlook offers the benefit of adding different types of the email account from a variety of servers like Exchange, IMAP, POP, SMTP, etc. When the user has connected the same account with an existing name and an alias in the same Outlook, then it is going to create the problem of duplicate items.

Recreating the same account

Sometimes, the account in Outlook shows some minor error and the user recreates the same account without removing the previous account, then both accounts may start receiving emails in them.

Importing PST file

If the user imports a PST file whose backup was recently taken, then it will have the same emails that are present in your inbox currently.

Improper Rule creation

Users can create some rules in Outlook for each type of received email. If a single rule is applied to the same email twice, then Outlook may enforce duplicity of emails.

Improper Account Settings in Outlook

In the Delivery section of the settings, if you check the option for ‘Leave a copy of the message on the server’, then it will create a duplicate of the message.

Methods to remove the duplicate items from Outlook mailbox

As we gave you many reasons for duplicate emails in Outlook, so you can remove them based on the situation.

Method-1. Stop Processing more rules.

There is an action to stop processing more rules. If you add the action to the first rule, then it will stop the second rule from processing even if it is true. Now whenever a rule is applied to the first message, then the action will stop the second rule from processing.
Stop Processing more rules

  1. Open Settings, and go to View All Outlook Settings.
  2. Go to Mails, then Rules, and click Edit.
  3. Click the checkbox Stop Processing More Rules.
Method-2. Remove the same account from Outlook.

If you have added the same account with different aliases, then you need to remove the second account and it will delete all the duplicate emails.

Method-3. Remove the duplicate PST file.

As you have connected the same PST file that has causes or reasons for duplicate emails in Outlook, then you should remove the second PST file and the duplicate emails will also go away.

Method-4. Disintegrate anti-virus with Outlook.

The anti-virus is the minor culprit that can integrate with Outlook and recreate the same email message if it finds any problem in the account. If the account is healthy, then you should disintegrate the anti-virus with Outlook.

Method-5. Repair the corrupt PST file.

If the duplicity has occurred due to the corruption in the email server, then the PST file will also be affecting by it. So, you should repair the PST file using Inbox Repair tool.


User need to find the reasons for duplicate emails in Outlook otherwise it can create multiple problems for your business and you should use the best method to remove them as soon as possible. When the PST file is corrupt, then the ScanPST tool cannot remove the complete corruption. So, you must use a special PST Repair tool that will remove the corruption from the data file and also delete the duplicate emails.

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About Barrett Clay

Barrett is passionate about technology and an admirer who believes in offering instant computing solutions to everyone. He solves personal and business technical issues related to IT products, applications, IT environments, platforms, technologies, etc., through well-documented blogs and articles, informative, authentic and descriptive content. He participates in technical content development, content publishing and marketing.

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