Remove Duplicate Emails From PST File – Quick Guide

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  • Updated On:
    April 12th, 2025
  • Read Time:
    5 minutes

As businesses expand, the teams have generated multiple PST Files for archiving messages over several years. Eventually, combining all these distinct PST files into a single archive will improve search efficiency. However, an issue arises after consolidating the PST files: Duplicate content. To keep the archive clean and easy to navigate, they have to remove duplicate emails from PST File. There are both manual methods and professional Outlook Duplicate Remover Tool that easily detect and remove the duplicates. Read the full blog to understand how users can remove the duplicates easily.

A PST (Personal Storage Table) is a file format used by Microsoft Outlook. It stores messages, contacts, and calendar events locally on the computer. It is primarily used to back up and archive Outlook data to access it offline. And, therefore, helps in managing the storage space.

What Factors Lead to the Duplication of Email Messages in Outlook?

Before we go deeper into the details of this blog post, it’s important to understand what factors cause the duplication of email messages in Outlook. Take a moment to review the points below to get a clear understanding: 

  • Emails can be downloaded twice in case of a misconfigured sync schedule and connection issues during synchronization.
  • Merging PST Files with similar timeframes can result in duplicate emails. 
  • Certain antivirus programs scan incoming emails and unintentionally download them again, creating duplicates. This occurs in case of POP3 connections.
  • Add-ins that are supposed to sync or back up data can sometimes malfunction and cause duplication of emails.

How to Remove Duplicate Emails from PST File?

You can complete this duplicate email detection either manually or by using a professional tool. While the manual process is possible, it can be complex and requires effort. Alternatively, using an automated tool makes the process faster and seamless. Let’s go through both the methods in detail.

Manually Delete Duplicate Emails from PST File

Follow these steps to delete duplicate emails successfully:

  1. Open Microsoft Outlook.
  2. Go to File > Open & Export > Open Outlook Data File.
  3. Now, select the PST File that you want to delete duplicates from.
  4. Navigate to each folder and sort them by subject, date, and sender while spotting the duplicates.
  5. Select the duplicates and delete them manually. 

Limitations: It is a time-consuming process and, therefore, is not ideal for large PST files. Also, this process is prone to errors as the user is manually deleting the duplicates one by one. 

Manually Remove Duplicates Using Outlook’s Import Feature

This method is useful when the user is importing a PST File and wants to skip duplicates.

Given below is the process to remove duplicate emails from a PST File:

  1. Open Outlook.
  2. Navigate to File > Open & Export > Import/Export.
  3. Choose Import from another program or file and select Outlook Data File.
  4. Then, choose Do not import duplicates.
  5. Complete the process.

Delete Duplicate Emails from PST File Using Outlook’s Clean-Up Feature

This feature removes redundant messages from email conversations and folders.

Below are the simple steps to initiate the process: 

  1. Open the Outlook application.
  2. Choose the folder from which you want to remove duplicate emails.
  3. Navigate to Home > Clean Up. Choose the desired Clean Up option.
  4. Finally, click on Clean Up.

Limitations: It does not remove the unread messages. This is only effective with threaded conversations.

Manually Use Search Folders to Find and Remove Duplicate Emails in PST File

Use the following steps to begin the process:

  1. Open the MS Outlook application.
  2. Navigate to Search Folders and right-click on it.
  3. Select New Search Folder > Create a Custom Search Folder > Choose > Criteria.
  4. Now, in the Search Folder Criteria, select the filter to search for the duplicates.
  5. Manually compare the contents, select the duplicate emails, and delete them. 

Professional Way to Remove Duplicate Emails from PST File

The Outlook Duplicate Remover Tool is a powerful solution that identifies and remove duplicate emails from PST file. This tool offers users the option to specify a duplicate criteria by like filtering by date, etc. It also provides a search function that helps users to quickly filter the duplicate email data. Users also have the option to preview the duplicate files detected before deleting them. Moreover, it supports mail and task filters while ensuring data integrity.

Quick and simple steps to delete duplicate emails from PST file:

  1. Download and run the tool.
  2. Select Single File and add the PST File from which you want to delete duplicate emails.
  3. Preview the emails in the preview panel and click Next.
  4. In the Additional Features section, go to Remove Duplicate Options.
  5. Pick the desired duplicate option and click Next.
  6. Choose the destination folder to save the file and, finally, click Next.

Conclusion

This blog explores two methods to achieve this: a manual method and an automated solution. The manual process involves complex technical steps and is slow. The automated Outlook Duplicate Remover Tool provides a faster and error-free duplicate detection to remove duplicate emails from PST File. It is a trusted, reliable, and error-free solution that is used by both individuals and businesses.

Related Post: Export Rackspace Email to PST Files.

Frequently Asked Questions:

Q- How do I delete duplicate emails in the Outlook PST file?

Ans- There are several ways to do it:

  • Using Outlook application
  • With the help of Outlook’s Clean-Up feature
  • Manually search folders and sort duplicates
  • A professional Outlook Duplicate Remover Tool

Q- What causes duplication of email messages in the PST file?

Ans- Various factors lead to this:

  • Misconfigured synchronization and connection issues.
  • Merging similar timeframe PST Files
  • Antivirus programs 
  • Add-ins malfunction
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About The Author:

Raj is a skilled technical writer who makes complicated topics easy to understand. With experience in email and cloud migration, he creates clear and engaging content that helps readers learn about technology. His work is trusted by many and has been featured on well-known tech sites.

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