What are the Reasons for Duplicate Emails in Outlook?

Ashwani Tiwari | Modified: June 4th, 2021 | MS Outlook

In this article, we are going to discuss the most common reasons for duplicate emails in Outlook. Since we know that emails are very important for any organization because most of the communication is done with it only.

Moreover, Microsoft Outlook is one of the top choices of users when it comes to choosing an email client. Because it provides lots of security features. But having duplicate emails in the inbox is one of the common issues faced by almost every email client user.

Now, suppose one morning you sit down in front of your computer as usual and launch Outlook for another fun-filled day of answering emails. But when you look in your inbox you find that inbox is filled with duplicates emails and this duplicate emails having the same subject, attachment, receiving time, and so on.

Unfortunately, the scenario is not an imagination cause many users are encountering duplicate emails issue in Microsoft Outlook.

Top Reasons For Duplicate Emails in Outlook

We have collected a couple of reasons that are responsible for duplicate emails in Outlook inbox. Some of them are listed below:

  • Outlook Server Issue- Sometimes a message on the server is corrupted. Or if the email server of Outlook failed to respond during Send/Receive the message then the next sync will download the previous emails again. This server issue causes duplicate emails in Outlook.
  • Wrong Account Synchronization- We all know that we can run Outlook on phones or tablets. So we start syncing our Outlook profile with our Phone or tablet but due to the wrong synchronization process, and the last batch of emails are present twice on your pc which one of the reasons for duplicate emails in Outlook
  • Mistakes in Outlook Rule – It might be possible that you define wrong rules during the configuration process of Outlook. This might result in data duplication in Outlook mailbox
  • Send/Receive Time Interval- If the update frequency of Outlook inbox is short, then emails will not get synchronized properly. This might be also the reason for duplicate emails in Outlook inbox.
  • Improper Account Setting- If you have configured the same email account multiple times in MS Outlook, then the incoming data will get synchronize again and again which is also one of the reasons for duplicate emails in Outlook that can also lead to duplicate email messages in Outlook mailbox.
  • Incorrect Import Process- During import emails from different Outlook data files in your current Outlook profile. And if the duplicate detection option is turned off, then Outlook skips the duplicate items which is one of the causes of duplicate emails in Outlook.
  • Wrong Forward Emails- If you forward your emails from one PC to another then the forwarding rule can create loops where the message is continually bounced back and forth between them that creates an infinite number of duplicates in Outlook inbox
  • Third-Party Antivirus- When you use a third-party antivirus program on the same machine that runs Outlook. The anti-virus can intercept the Send/Receive process of Outlook that is one of the reasons for duplicate emails in Outlook

Also Read: How to Prevent and Remove Duplicate Items from Microsoft Outlook?

How to Remove Duplicate Emails in Outlook?

After knowing what are the reasons for duplicate emails in Outlook. Now, everyone wants to know how to remove it. But the sad news is that Outlook does not provide any solution to delete duplicate emails from Outlook.

Hence, to remove duplicate emails in Outlook you have to pick out all the duplicates emails and you delete them manually. This manual method is effective when you have a fewer number of emails saved in your inbox.

But if you have a large number of emails saved in your inbox, then the manual method is so time-consuming. And what if you later find that you deleted a message which only looks like a duplicate by mistake?

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So, to make things easier try professionals suggested tools to delete duplicate emails in Outlook i.e., Outlook Duplicate Email Remover Tool. It is a tool that removes duplicate emails, contacts, calendars, tasks, journals, notes from Outlook PST/OST/BAK files.

Now let’s see the steps

  • Download and install duplicate remover on a local machine.
delete duplicate emails
  • Click on the Add Files or Add Folder button to add PST/OST/BAK files.
reasons for duplicate emails in outlook
  • Select the duplicate criteria from the Select Filter and Duplicate Criteria option.
select filter
  • Now, select properties from Specific Duplicate Criteria options.
reasons for duplicate emails in outlook
  • After all the settings, click on the Next button to start the process of remove duplicate emails in Outlook


As you have noticed that in order to help you out,  in this blog, we have discussed all the reasons for duplicate emails in Outlook. In addition, we have also discussed an effective way to remove duplicate emails from Outlook. So, get your license of the tool today and get rid of duplicate emails from Outlook.