September 28, 2023

How to remove OST Duplicate files from the Outlook OST?

Microsoft Outlook’s OST (Offline Storage Table) file is a local copy of the user’s mailbox that is kept on the user’s computer. The OST file shouldn’t duplicate automatically or by default under typical conditions. However, under the following circumstances, you could come across duplicate OST files:-

Reasons to Create Duplicate OST Files:

  • Manual Copying or Backup: Users have the option of manually copying or backing up an existing OST file to another location or storage device in order to create duplicate OST files purposefully. This is frequently carried out for migration or data security considerations.
  • Duplicate OST files may occasionally be created:-  As a result of synchronization problems between the Exchange server and the Outlook client. Network difficulties, software bugs, or disagreements between the server and the client might all be the cause of these problems. Instead of updating the current OST file when the synchronization process finds difficulties, it could try to generate a new one, which leads to duplication.

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It’s vital to remember that duplicate OST files can eat up extra storage space and, if improperly maintained, may result in confusion. To prevent any data inconsistencies or performance issues, it is advised that you thoroughly analyze the reason for any duplicate OST files and then take the necessary actions to either fix the underlying problem or remove the duplicates.

Two ways to remove duplicate OST emails from OST files:-


  • To remove duplicate OST emails manually, you can follow these steps:
  • Open Outlook.
  • Click on the “File” tab.
  • Click on “Open & Export”.
  • Click on “Import/Export”.
  • In the “Import and Export Wizard”, select “Export to a file”.
  • Select “Personal Folder File (.pst)” and click on “Next”.
  • Select the OST file that you want to export from the “Select the folder to export from” list.
  • Select the “Delete duplicates from the folder” option and click on “Next”.
  • Select the exported PST file’s destination folder and click “Finish”.

Using a third-party tool

There are many third-party tools available that can help you to remove duplicate OST emails. Some of the most popular options include:-

TrustVare OST Duplicate Remover’s best Features are…

  • These tools typically offer a number of features, including:
  • The ability to scan OST files for duplicate emails
  • The ability to preview duplicate emails before the removal
  • The ability to remove duplicate emails in a single click
  • The ability to save the extracted emails to a PST file
  • The best third-party tool for you will depend on your specific needs and requirements.

To use a third-party tool to remove duplicate OST emails, you will typically need to:

  • Download and install the TrustVare OST Duplicate Remover Software.
  • Add the OST file that you want to scan for duplicate emails
  • Click on the “Scan” button
  • Wait for the scan to complete
  • Select the duplicate emails that you want to remove with “Remove across folder”, “Remove each folder”
  • Click on the “Remove Duplicate Mail” button
  • Save the removed emails to a PST file if desired
  • Once you have removed the duplicate OST emails, you can free up space on your computer and improve the performance of Outlook.



The OST Duplicate Remover tool can quickly remove many OST emails at one time. Some users do not need to install other software to eliminate OST files. It can work with all Windows or MS Outlook versions, whether new or old. Both technical and non-technical users can also use this tool to remove OST files. This application also gives a free demo version to all users so that they can know more features and functions of the software.

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