How to Reduce PST File Size Without Data Loss

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  • Updated on July 23rd, 2025

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Summary: PST stands for portable storage table created in MS Outlook to store data like email messages, tasks, calendars, contacts, etc. However, sometimes users face problems with large PST files like inaccessibility. Hence, in this article, we will describe the simple and reliable ways to reduce PST file size using Outlook. We will also include an automated approach with an outstanding PST Compact Tool that can solve your problems with utmost security.

MS Outlook is a desktop-based email service provider quite popular among huge organisations and professionals. It is used by many individuals who face issues of inaccessible PST files due to exceeding storage limits and errors because of oversized PST files. So here we will be describing the various methods that can reduce Outlook PST file size without losing any data. Therefore, read this blog to the end to find the methods, which include how to shrink Outlook PST files with and without Outlook.

Methods to Reduce PST file Size With & Without Outlook

There are various procedures to compress a PST file with the help of Outlook’s built-in features and without it. So let’s move forward to learn the secure and easy-going methods to reduce the size of a PST file in Outlook.

Method 1: Use Compact Now Feature of Outlook

MS Outlook has a built-in feature to compact PST files so let us first learn this process without any delay.

  1. Open Outlook and go to File >> Info >> Account Settings.
  2. Choose Account Settings again and click on the Data Files option.
  3. Select Settings and then choose the file you require to reduce and click Compact Now.
  4. Lastly, Click on OK to complete the process.

Method 2: Archive Outlook Emails

This is another built-in feature provided by Outlook that can reduce the size of your PST files, so follow the mentioned steps below.

  1. Open Outlook and go to the File menu.
  2. In the Info section, click on Tools >> Clean Up Old Items.
  3. Select the Archive this folder and all subfolders option and choose the folders you require to archive.
  4. After that, tick the Include items with the Do not Auto Archive option to archive only selective folders.
  5. At last click OK to complete the procedure.

These are two manual methods that Outlook provides to compact the size of a .pst file. However, the above procedures are quite time-consuming, and there are chances of heavy data loss on any manual mistake. Moreover, sometimes users face issues like misplacement of information while performing these methods. Therefore, we have also included a professional approach to reduce PST file size without Outlook.

Method 3: Professional Way to Reduce PST File Size Without any Data Loss

PST Compact Tool is an astonishing tool that allows you to compress Outlook PST files with reliability and 100% data integrity. It offers a very user-friendly interface that helps non-technical users easily operate this tool. Using this software, you can easily compress multiple PST files simultaneously with attachments. One of the benefits of this utility is that it supports PST files created by all versions of Outlook.

Step-by-Step Guide to Compress PST File

  1. Download and Install PST Compress Tool.
  2. Click the Select Files button to browse single and multiple Outlook Data files to compress.
  3. Here, select the folders from the tree structure and preview the details and then click on the Next.
  4. Choose the Compress option as per your requirement.
  5. You also have the other option to include the built-in features provided by the software.
  6. Finally, click the Start Compression button to reduce the PST file size.

Conclusion

To reduce PST file size, we have included various procedures that can efficiently compact the size of any PST file with ease. Manual methods can compress PST data using different features of MS Outlook. However, these methods are quite risky if you have multiple files to compress. Therefore, we have also included a professional solution that offers you a safe and secure process of compression of Outlook PST files in bulk. Well, it’s up to you to choose any of the above solutions.

Also Read: Outlook PST Cannot be Found.

Frequently Asked Questions:

Q: What is the safest way to reduce the size of a PST file without losing any data?

A: The safest way is to use Outlook’s built-in Compact Now feature after deleting unnecessary items. This compresses the PST file without deleting any data that remains in your folders.

Q: Can I reduce PST file size without deleting emails or attachments?

A: Yes. You can archive old emails, move items to a new PST file, or compress the PST file using “Compact Now” to reduce size without deleting data.

Q: Will archiving emails help reduce the size of my main PST file?

A: Yes. Archiving moves older emails to a separate PST file, effectively reducing the size of your main Outlook data file while preserving all data.

About The Author:

Evren Cole is an expert in Email and Data Management. She has a strong passion for technology and entrepreneurship. In her free time, she enjoys football, music, and reading books.

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