How to Reduce Large PST File Size without Deleting Data?

  Anjali Rawat
Anjali Rawat   
Published: April 27th, 2026 • 5 Minutes Reading

If you are also frustrated with a large PST file size and want to reduce it, then you are on the right page. You can easily reduce PST file size by using the archive option, the Compact Now feature, moving attachments locally, and splitting into smaller parts. We will discuss each method one by one in the upcoming sections.

Large PST file size is a very common issue with Outlook users, and it happens due to multiple reasons, such as:

  • Unmanaged Inbox
  • Large attachments
  • Holding old emails
  • Caches and cookies

Reducing PST file size is not an easy task, but we have made it for you. This write-up will explain complete information with a step-by-step guide. Let’s start it….

How Does Large PST File Size Impact?

An oversized PST file affects the performance, stability, and usability of Outlook. Here is why it is important to reduce PST file size:

  • You will not be able to receive and sending emails.
  • Your Outlook is continuously freezing and hanging.
  • Slow down your Outlook performance
  • Also, a large PST file size contains a high risk of corruption.
  • You can’t use functions like search, copy, etc.
  • Affects overall productivity and workflow

Instant Way to Reduce PST File Size without Outlook

If you don’t want to delete data from the file and want to shrink the size, then splitting is the best way. Because if you compress the file size, it will again grow after some time. But dividing into smaller files helps users to access only the required file whenever needed.

And PST Splitter Tool is the only possible way. It helps to reduce large PST files without Outlook size by dividing as per size, date, year, folder, category, email ID, etc. Try the demo version to understand how the tool works.

How to Shrink Large PST File Size Manually?

If you can easily access your Outlook account without having any issues, then you can use these manual techniques for a large PST file size:

  • Archive Data
  • Compact Now Feature
  • Move Attachments
  • Cutting Large PST File

Method 1: Archive Old Data Separately

Archive is a built-in feature of Outlook, which allows you to save old data into a separate PST file. Use the given steps to reduce PST file size:

  1. Open your MS Outlook.
  2. Head to the “File” tab and choose the “Info” option.
  3. Choose the “Tools” >> “Clean Up Old Items”.
  4. Choose the “Archive this folder and all subfolders” option.
  5. Select the folder that contains old data.
  6. Set the date under “Archive items older than”.
  7. Select a location to keep your PST file
  8. Hit the “OK” button to start the archiving process for the large PST file.

Method 2: Compact Now Feature to Reduce PST File Size

  1. Choose the “File” tab in Outlook.
  2. Select the “Account Settings”“Account Settings” options.
  3. Hit on the “Data Files” option.
  4. Choose your PST file.
  5. Hit on the “Settings” and choose the “Compact Now” option.

Method 3: Move Attachments Locally

  1. Open your MS Outlook.
  2. Choose the email that contains attachments.
  3. Right-click on the attachment.
  4. Choose the “Save As” option and select a location.
  5. After saving the attachment locally, now right-click>> select the “Remove Attachment” option.

Why Manual Methods Don’t Work?

  • Yes, you can use these techniques to reduce PST file size, but manual techniques contain multiple setbacks:
  • These methods don’t work with bulk data files.
  • It requires following the same process again and again for each file.
  • Also, the removal of attachments method contains a high risk of losing data or accidental deletion.
  • These techniques don’t provide advanced filters for specific data.

How Will Software Reduce PST File Size?

Manual methods only fix the issue for a short time, which means after some time, your file will grow again. So, the suggested solution divides your file into smaller parts so you can easily access only the required part whenever you need. It prevents your file from becoming large with data. This solution comes with a free demo version, so you can understand how it works.

How to Fix Large PST File Size Issue?

  1. Download and start the software on your system properly.

    tool to reduce outlook data file size

  2. Choose the “Add Files” and “Add Folders” options to import large files.

    add file

  3. Select the location using the “Browse” button and continue with the “Next” icon.

    location

  4. After that, choose “Split Option” according to your requirements.

    split option

  5. Select the “Next” icon, and lock your file with a password.

    lock your file

  6. Hit the “Split” icon to reduce the PST file size easily.

    reduce pst file size

What Are the Top-Notch Features?

  • The software supports both ANSI and UNICODE PST files.
  • It can handle any size of PST files from 1 MB to 1 TB smoothly.
  • It allows dividing files by size, year, date, folder, category, email ID, subject, and sender.
  • This tool maintains folder structure and file components without altering any information.
  • It supports all types of PST files, including orphan, damaged, corrupt, and inaccessible.
  • Also, this software can handle multiple files at the same time without repeating the process for each file.

Conclusion

This blog has explained the best and possible methods to fix the large PST file size using manual and automatic solutions. Manual techniques are best for those files that can be opened with Outlook smoothly. In case you are facing issues with Outlook, like freezing, not responding, hanging, etc., then you should use the automatic solution to reduce PST file size. This solution doesn’t require deleting any data; it just divides your large file into smaller parts.