Table of Content
    Repair PST File

    Steps to Remove Duplicated Email Messages in Outlook 2016

    Table of Content

      Summary: The guide highlights some common reasons resulting in identical, duplicate email messages in Outlook 2016 and the challenges you may face due to such messages. It also mentions some easy steps to remove duplicate email messages from Outlook.

      Are you experiencing email duplication issue in your Outlook 2016 mailbox?

      While this may not seem a serious problem in the beginning, accumulation of duplicate email messages can pose challenges.

      Easy Solution: Try Stellar Toolkit for Outlook to fix all Outlook issues like Duplicate emails, missing emails, conversion of OST file, corrupt PST, lost Outlook password & many more.

      What Happens when Duplicate Emails Occur in Outlook 2016/2013/2010?

      Following are some challenges you may face due to redundant or multiple emails in Outlook:

      • Affect the overall performance and productivity of the Outlook application hence it becomes necessary to delete multiple emails in Outlook.
      • Increase mailbox size, which may lead to data file corruption and Outlook hanging issue.
      • Since business users have to deal with numerous email messages and reply to each message, having the same copy of emails may result in the duplicate effort. Meaning, business users may end up replying and responding to the same message repeatedly.

      Before proceeding with ‘How to remove duplicate emails in Outlook?’, it is crucial to understand the actual cause of the problem. Once you have detected the cause, you can apply an appropriate workaround to delete multiple emails.

      Possible Reasons that Result in Duplicate Emails in Outlook 2016/2013/2010/2007

      Some common reasons that can lead to duplicate emails in Outlook are as follows:

      1. Incorrectly Configured Rules

      Creating incorrect rules in Outlook is the most common reason that can result in data duplication in the Outlook mailbox.

      2.  Short Send/ Receive Intervals

      When the frequency between sending and receiving of data is set for a short time, suppose less than 5 minutes, you may face email duplication problem. The problem occurs because when Outlook is processing the request to send/receive first email uploaded in the mail server, the next send/receive process gets started before finishing the previous one.

      3. Multiple Account Creation

      Configuring the same email account on multiple systems can cause incoming data to synchronize repeatedly. Due to this, you may receive multiple copies of duplicate emails in Outlook.

      4. Improper Mailbox Settings

      Due to incorrect settings of the mailbox, while creating a user account, you may receive the same email message, calendar entries, or contacts multiple times.

      5. Using Third-Party Anti-Virus Scanner

      When an anti-virus program is set on the same machine that runs Outlook, the possibilities are that it will intercept ‘Send/Receive’ requests in Outlook. So, when Outlook sends and receives a message, it thinks it is communicating to a mail server. But, the email client is actually communicating with the anti-virus scanner. This means that the virus scan solution is responsible for closing down connection to the mail server.

      If the connection is not shut down properly, the ’email message is not flagged as received’. This leaves you with the possibility of receiving the already received message again during the next Send/Receive cycle.

      Steps to Remove Duplicate Emails in Outlook 2016/2013/2010/2007

      Follow the steps in the same sequence as below to remove duplicate messages in Outlook mailbox:

      Step 1: Configure Rules Correctly

      Check the Outlook Rules to ensure that they are not configured incorrectly as this creates confusion among various email folders.

      Step 2: Set Inbox Update Frequency

      Increase Inbox update frequency by following the given procedure:

      1. Open Outlook, and click Send or Receive.
      2. Next, select Define Send or Receive Groups.
      3. Set ‘Schedule an automatic send/receive every’ value to anything between 15 and 30 minutes.

      Step 3: Run Inbox Clean Up

      MS Outlook comprises several utilities and add-ins that can help clean duplicate emails in MS Outlook effectively. Clean Up is one such built-in utility that helps in removing duplicated inbox email messages. Here’s how you can use this utility:

      1. Open MS Outlook 2016.
      2. Select the Inbox folder that contains duplicate emails.
      3. Click the Clean Up option on Home menu. Next, select any one option based on the occurrence of duplicate items:
      • Clean Up Conversation: This will delete and move duplicate email messages existing in the conversation to Deleted Items folder.
      • Clean Up Folder: This option will allow you to delete duplicate email messages from a particular folder.
      • Clean Up Folder and Subfolders: It will clean up folders as well as subfolders.
      1. Next, right-click the Deleted Items folder and select the Empty folder option to delete the duplicate email messages permanently

      Step 4: Disable Virus Scanner Integration with Outlook

      As discussed above, a virus scan solution integrated with Outlook can intercept Send/Receive request. This may cause the download of identical messages.

      To resolve this, go through the anti-virus instruction manual to check the procedure to disable email protection. Once the email protection is disabled, wait for previous Send/Receive cycles to complete. And then, make sure that duplicate messages are no longer received and check if the anti-virus program is running as expected.

      To Delete All Email Messages or Duplicates Refer to this Manual Guide

      Step 5: Use a Professional Outlook Toolkit

      Stellar Toolkit for Outlook is a potential solution to eliminate duplicate emails in Outlook. It not only removes the identical messages but also removes junk files and makes Outlook more productive. No data is ever compromised, as the tool is engineered using smart and powerful algorithms that detect duplicate emails and removes them efficiently.

      Free Download

      Essentially, the toolkit is a complete package that helps resolve multiple Outlook mailbox problems. It offers a number of functions such as repairing PST file, splitting PST into smaller proportions, compact or compressing the PST file size, merging PST files, and recovering lost or forgotten passwords, etc.

      It can be downloaded and installed on Windows 10, 8, 7, Vista and XP, and lower versions. The software is compatible with MS Outlook versions 2019/2016/ 2013/ 2010 /2007 /2003.

      The Bottom Line

      MS Outlook email duplication is a common issue that can occur in any Outlook version. It can affect the functionality, productivity, and performance of the email application. And so, it becomes important to remove duplicate emails.

      Although manual workarounds are available, implementing all of them to fix removing multiple emails in outlook, can take a lot of time. Plus, the integrity and the importance of email messages are always at stake. But, by using a reliable Outlook duplicate remover tool such as Stellar Toolkit for Outlook, you can quickly remove duplicate email messages in Outlook 2016 and other versions.

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      About The Author

      Eric Simson linkdin

      Eric Simson is an Email Platform Consultant and is associated with Stellar Data Recovery from last 6 years. He writes about the latest technology tips and provides custom solutions related to MS Outlook, MS Exchange Server, Office 365, and many other Email Clients & Servers.


      1. Hi Eric & co.
        I am a perfect case study for Stellar… I use my inbox as my unsorted (KWIC-searched everyday) recepticle for my professional life… and I like to keep access to over a decade of correspondences… for years it was my local Exchange server, but we migrated to O365 (now Microsoft 365) 2 years ago.

        My box (finally) crashed yesterday. Those rats in Redmond lied (!) when then promised me 99 gB of data, I got locked at 97.8 gB. Ok, what’s 500K messages in an inbox gonna do?

        Adding insult to injury, the 100 gig is not “all” of the email I would like to access… but in reality there are many dupes so I probably have <25 gig of real stuff…

        But I need to collect all my emails, dedupe, think about attachments, and then make a clean and tidy inbox (with great searching).

        How can you and your products help?


        p.s. I also have gmail stores that I pulled off of M365 to save space… so I am probably working with gross 150 gig of emails… and ~750K emails.

        1. Hi David, please confirm whether you trying to convert individual mailboxes or want to convert the complete exchange database.
          We do have Stellar Converter for OST for individual mailboxes(OST) and Stellar Repair for Exchange(corrupted EDB) Stellar Converter for EDB (for working EDB).

      2. I don’t think Outlook’s built-in Clean Up tool is good for removing duplicates. It’s intended to remove emails that are completely contained within other emails, ie have been quoted in their entirety. I tried it, and in many cases, it removed BOTH copies of duplicated emails.

        I suspect it just does a simple test to see if an email is completely contained in another email, then removes it if it is. This test is true for both copies.

        1. Hi Peter,

          Thanks for sharing your experience with the built-in Clean Up tool.
          Have you tried other suggested workarounds to remove duplicate email messages?

      3. hi,
        I have purchased the Stellar DeDuplicator for Outlook but it has not recognized any duplicated email so far…
        What to do?

        1. Hi Fatjon,
          Please provide the following details so that we can analyze the issue:

          • Outlook version installed in your system?
          • Is it 32 or 64 bit?
          • Make sure the PST should be selected as default from which he wants to remove the duplicates.
      4. Great!

        This same solution is doing a great job to recover duplicate emails in MS Outlook 2019. You guys saved my hard earned money.

        Again thanks for your wonderful support!

      5. We feel that duplicate emails are also responsible for human errors due to confusion. So, Our team will register a full license key of the software asap.

        1. Hi Lily,

          Thanks for sharing your genuine feedback & challenges with us. We always encourage the end users to share their problems with us. After understanding the real world problems, we are doing our best to make the software more powerful & user-friendly.

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