How to Remove Duplicates items in Outlook? Problem with duplicates items, they increasing my PST file size, and its very difficult to find a specific email items in outlook. How i remove these email items accurately.

How do I remove duplicate emails in Outlook? If you've been dealing with duplicate emails in your MS Outlook, they've probably frustrated you to bits. Duplicate emails increase your PST file size and makes it difficult to find specific emails. But don’t worry, this article will discuss reliable ways to find and delete duplicate emails in Outlook.

How do I remove duplicate emails in Outlook? If you've been dealing with duplicate emails in your MS Outlook, they've probably frustrated you to bits. Duplicate emails increase your PST file size and makes it difficult to find specific emails. But don’t worry, this article will discuss reliable ways to find and delete duplicate emails in Outlook.

Part 1: Why Are There So Many Duplicate Emails in Outlook?

1.Creation of Multiple Accounts

Having two different email accounts under one Outlook can lead to synchronization of the incoming data. That especially happens if you've configured your work and personal email. What does this mean? You may receive multiple copies of the same email in Outlook. That's why you should ensure all your email accounts appear separately and not aliases for the same Outlook.

2.Improper Settings in your Mailbox

When creating a user account, you will receive the same contacts, calendar entries, and emails in duplicates if you input incorrect settings. If you have enabled the checkbox "Leave a copy of the messages on the server," you will receive duplicate Outlook emails. Fix the issue by disabling the feature in your MS Outlook account settings.

3.Short Send/Receive Intervals

Email duplication sometimes happens when the send/receive data frequency interval is too short. For instance, if your send/receive interval is less than 5 minutes, you will likely experience this problem a lot. That's because as Outlook is processing the send/receive request for the first email in the server, another send/receive request is initiated even before the first one is complete.

4.Use of Anti-virus Programs

If you have an antivirus program on the computer running your Outlook, it may intercept the Outlook Send/Receive requests. Often the antivirus program closes down the mail server connection. And if the email was not already flagged as received, you might receive the same email again during the next send/receive cycle.

Part 2: What Happens if There are Too Many Duplicate Emails in Outlook?

When there are too many duplicate emails in your Outlook, you may encounter the following challenges;

  • Duplicate emails occupy space in the Outlook Data File PST. That slows down the overall efficiency and productivity of your Outlook application
  • You will need to increase your mailbox size to archive or back up data. However, there’s a risk of data corruption and slow performance of your Outlook
  • Too many duplicates in Outlook folders complicate the search and indexation of data in Outlook

Part 3: How to Delete Duplicate Emails in Outlook

Way 1: Delete Duplicate Emails in Outlook Manually

Microsoft has no automatic means to remove duplicate emails in Outlook. If Outlook is receiving/sending emails in duplicates, you'll have to manually disable the 'Double Sent Items' in Outlook. Follow the steps below to stop Outlook from saving duplicate emails in the 'Sent' folder.

  • Launch the Outlook application and go to the 'File' tab

  • Click on the 'Info' section

  • Click on Account Settings, then Manage Profile

  • Select your IMAP account

  • Go to 'Change' then 'More Settings'

  • vi.In the 'Advanced Settings', uncheck the 'Do not save copies of sent items.'

Way 2: Configure Rules in a Correct Way

Improper configuration of Outlook settings is one of the main reasons why you're getting duplicate emails. So, check to see if all the rules are well configured.

To clear the confusion, in the settings, disable the 'Leave a copy of messages on the server' as when this feature is enabled, it creates copies of all sent and received emails.

Way 3: Disable the Antivirus Email Scanning Option

If your system has an antivirus program, you must disable it to eliminate the duplicate emails issue. Antivirus often causes server timeout, especially if emails are being received in a large size. If the server timeout occurs before flagging the email as read, you will likely get the same email repeatedly.

Way 4: Run an Inbox Clean Up

Outlook has several add-ins and utilities that help run an inbox clean-up. Clean Up is one of the add-ins on Outlook that help remove duplicated email messages from the inbox. Here are the steps to follow;

  • Launch your MS Outlook application and select an inbox folder with duplicate files

  • Go back to the Home menu and click on the 'Clean Up' tab

  • If you select Clean Up Conversation, all duplicate emails in this section will be moved to Deleted Items. If you choose Clean Up Folder, the option will allow you to delete duplicate emails in Outlook from a specific folder. In that case, you can select Clean Up Folders and Subfolders

  • Go to the Deleted Items folder. Right-click and select Empty Folder to permanently remove duplicate emails in Outlook.

Way 5: Use of a Third-Party Software

Kernel for Outlook Duplicates Remover Tool is one of the best professional solutions for removing duplicate files in Outlook. It's an automated solution that eliminates duplicate emails from the Outlook PST files.

  • Create a new task on Kernel for Outlook Duplicates

  • Choose an action to be performed on the duplicate items

  • Save your report


Part 4: Bonus Tips- How to Remove Duplicate Files on Your computer new

If you've ever tried removing duplicate files from your computer manually, I bet you understand how hectic that can be. Luckily, it doesn't always have to be that way. We have robust software in the market that can help you easily remove duplicate files. PassFab Duplicate File Deleter is one of the best software for finding and deleting duplicate files on your PC. This software stands out from the rest as;

  • It can easily find and delete duplicate files and images.
  • It works with 100% accuracy on all file’s formats, including audio and video.
  • The software can be supported on Windows 11/10/8.1/8/7 and MacOs 10.11-13.
  • The duplicate files deleter is compatible with laptops, external and internal hard drives, and USB flash disk.
  • Download then Install the Software

    click to add a folder

    Once installation is complete, launch the Passfab Duplicate File Deleter, and you'll see the 'Click to Add a Folder' button on the interface.

  • Add the Scanning Folders

    add scanning folders

    Select and drop the files you'd like to add for scanning with the duplicate file deleter. You'll be able to see all the files you've added to the interface.

  • Set the Scanning Modes

    set general

    Choose your preferred scanning modes from the three available options; General, Ignore Scan, and Duplicate Files.

  • Delete Duplicate Files

    scanning duplicate

    The scanning process will take a few minutes before all identified duplicate files appear on the interface. The software allows you to preview and compare files before deleting them individually. Once you confirm the files you'd want to delete, click on Remove Files.


Email duplication in Outlook is a common problem that slows down the email application's productivity, performance, and functionality. That's why you should find a reliable way to remove duplicate emails in Outlook.

Although there's a manual workaround, it can be frustrating and time-consuming. You'll have an easier time relying on a third-party duplicate remover tool to remove duplicate emails in Outlook.

That aside, if you have duplicate files that are slowing down the performance of your computer, you can consider Passfab Duplicate File Deleter as it's the best duplicate file deleter in the game.