How to Delete Duplicate Emails in Outlook 2013, 2016?

When you transfer items in MS Outlook, and the duplicate detection option is not enabled or turned on. Then Outlook leaves the duplicate items. Once the data is moved completely, you cannot eliminate the duplicate items so easily. So here, we will focus on how to delete duplicate emails in Outlook 2013. And in all its versions. So read this blog carefully to deal with your issue easily.

But before we discuss solutions to remove duplicate emails in Outlook 2016 and in its later or previous versions. Let’s check out what problems you have to face due to these duplicate items.

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Problems faced due to Duplicate Emails

Microsoft Outlook is one of the complex applications served with Microsoft Suite. To perform evenly, Outlook needs loads of resources. Outlook users generally face duplication of messages and emails regularly. You will face the below-listed problems for such issues.

  • Duplicate emails create confusion. The user cannot be sure whether the email was replied to or not. If you reply to the same email again and again. Then it will create more confusion between the team members and clients.
  • If the Outlook is set up with Exchange Server or Office 365. Duplicate items will enlarge the size of the Exchange/Office 365 mailbox.
  • Duplicate emails enlarge the size of the Outlook data files uselessly. And make the Outlook application slower. It badly affects the productivity of the business. It consumes more and more time to access the new emails and reply to them.
  • The Outlook backups will acquire more space. And if you save backups at any external cloud storage, then you have to pay more for that extra space.

Here we discussed what problems we face due to the duplicate emails. Now let’s see the reasons why duplicate emails occur. And after that, how to delete duplicate emails in Outlook 2013, 2016?.

Reasons for Duplication of Email Messages

There are numerous reasons that result in duplication of emails. But some of the common reasons for the issue are discussed below:

  • Inappropriate setup of rules:
    If the rules are not set up correctly, it creates confusion when you receive an email message. And results in duplication of the emails.
  • Short intervals in sending and receiving messages:
    If the inbox updates with low frequency, the emails and other data in the mailbox are not synchronized, resulting in data duplication.
  • Error in the account setup:
    If the same email account is used for various devices such as laptops and mobile, then it leads to repeat synchronization of the incoming message. This is one of the major reasons for email duplication.
  • Inappropriate settings of the mailbox:
    When you create an account in Outlook, and the mailbox parameters are not set properly, it is likely to receive the same email and any message repeatedly.
  • Technical Problems:
    The technical problems in the mail server also cause the duplication of Outlook email items. Such cases occur regularly if you activate the option of “Leave Messages on the Server.” The inappropriate setup of Microsoft Outlook is coordinated when two or more “move a copy to” rules are applied to certain incoming emails. This probably causes duplication of emails. Duplication of emails is also due to the combining of numbers of PST files into a single file.

Whatever be the reason behind the duplication of emails, it will badly affect the productivity of Microsoft Outlook. Therefore, you must remove duplicate emails in Outlook 2016, 2019, and its previous versions. Let’s discuss the solutions to remove duplicate emails.

How to Delete Duplicate Emails in Outlook 2013, 2016, and it’s all versions?

Before you delete the duplicate items of Microsoft Outlook, you need to reach the cause and resolve the issue. Here we discuss the five methods to eliminate duplicate files from Outlook mailbox.

1) Set -up the rules properly:

Make sure whether the Outlook rules are set up correctly or not. If rules are not set properly. It will generate confusion among different email folders. Set up the rules correctly.

2) Configure the inbox updates frequency

Increase the inbox update frequency. Initiate Outlook and then go to Send and Receive. Now choose Define Send or Receive Groups. Now configure the value within 15-30 minutes.

3) Clean Up inbox

Outlook has many tools and add-ins. That helps you to clean up or remove duplicate emails easily. Follow the below-listed steps to clean up your mailbox:

  • Initialize Outlook.
  • Choose a mailbox folder.
  • Choose Home > Cleanup. Now, set up the below options:
    • Clean up Conversation will eliminate and move the duplicate emails in the Conversation.
    • The Clean Up Folder will eliminate the duplicate emails from any certain folder.
    • Clean Up Folders and Subfolders will clean the duplicate folders and subfolders.
  • Now, Right-click on the Deleted Items folder and Press on the Empty Folder that will permanently delete the emails.

4) Antivirus Application

If there are duplicate files in your mailbox, it can be due to the server connection’s closing and the Antivirus application’s settings. If the server connection is not closed correctly, then emails that are not flagged as received will generate duplicates. To fix the issue or remove duplicate emails in Outlook 2016 and all its versions, you just go through the manual Antivirus software and disable the email protection. Professionals never suggest these steps, as disabling the antivirus can result in serious problems if any virus or malware attacks your system through an email.

The methods mentioned earlier are the manual approach that will fix your issue for removing duplicate emails in Outlook 2013, 2016, and its versions. But these methods are not that safe and secure. Especially if you are a novice user. So professionals recommend using third-party utilities such as PST Duplicate Email Remover. This tool eliminates duplicate emails in Outlook from multiple and single PST files quickly and safely.


Here in this blog, we focus on fixing the issue of how to delete duplicate emails in Outlook 2013 and all its versions. Professionals always suggest using automated tools for such an issue. But you are free to use any method as per your need.