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How to Reduce Size of Outlook PST Files Effortlessly?

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Written By
Nick Rogers
Published On
November 18th, 2025
Reading Time
6 Minutes Reading

Note: This informative blog is all about how to reduce size of Outlook PST files.

Imagine this: You open your Microsoft Outlook app on a busy Monday morning, ready to check your work-related emails but instead of loading smoothly, the emails take a long time. Annoying right? Most of the time, the real culprit behind this issue is the oversized PST file.

Just like a suitcase that becomes very difficult to carry when you load it up with too much stuff in it. Outlook PST files also become very heavy with large attachments, headers, and more. The bigger the PST files get the more problems they create.

Are you one of them having issues with large PST files? Need to get rid of this? If yes, you should keep reading the blog. Here, we are going to explain this topic how to reduce the size of Outlook PST files. We will provide the best methods to accomplish this task.

Common Reasons Behind Growing PST Files in Size

Large Attachments

  • PST emails with large attachments such as PDFs, videos, photos, and more.
  • Multiple versions of same attachments stored repeatedly.

Embedded Image in PST Email

  • Signatures with logos.
  • Inline images in newsletters or marketing email messages.

Email Header

  • Every email contains headers (From, To, CC, Message-ID, servers it passed through, etc.). These headers take up a lot of space and make the Outlook PST file large in size.

Common Issues You Face with Large PST Files

  • A large PST file can easily slow down Outlook performance.
  • Outlook may stop responding or close unexpectedly especially when you try to open a large email.
  • The larger the PST file, the higher the chances of getting corruption.
  • Large Outlook PST file takes a lot of time to backup and restores.
  • If you want to move your emails to another computer, a large PST file may be slow and sometimes fails to export correctly.

Now, after knowing the reasons of pst file size grow and problems arise when pst file size, then the question is how can we get rid of this? Is there a solution? And the answer is yes. There is a perfect and all-in-one solution available to reduce size of Outlook PST files.

A Perfect Solution to Reduce Size of Outlook PST Files

Well, many solutions are available that help to compress PST file size but most of them contain several limitations. For this we have developed a perfect and all-in-one solution namely 4n6 Email Compressor which can help you reduce the size of Outlook PST files without facing any kind of issues. The application offers several ways to reduce the PST file size without affecting the content and other information. This software has a very simple graphical user interface. You will not face any kind of issues when using it to compress Outlook PST file size.

Step-by-Step Way to Compress Large PST Files

Quick Tip: It is recommended that you first download and check the trial edition of the PST 4n6 Compressor Software. This trial version is added to test the features and functioning of the tool without investing anything. So, download it now and follow the steps below.
  • After downloading, follow all the instructions and install the software properly on your system. Run it and click the Open button.
  • When you click the Open button, you will be presented with a list of different formats. Please choose the Outlook PST file option.
  • Now, the program allows you to browse the PST files you want to compress.
  • The tool quickly loads the selected Outlook PST files on the left panel. You can click on them and preview them before compressing them.
  • Now, click on the Actions button and choose the Compress Emails option from it.
  • Please check the uploaded files on the left panel and select the option to compress PST files.
  • Choose the location and click on the Save button to start compressing Outlook PST files.

When the compression is finished, you will get a completion message.

Advantages of Using 4n6 PST Compressor Software

  • This software is highly tested and free from any kind of risk. You should feel free while using Outlook PST files size reduction software.
  • The software allows you to remove all attachments from the PST file to compress the email size.
  • This software has a very simple graphical user interface. Technical and non-technical users can easily use this software without facing any problems.
  • It successfully supports compressing inline images embedded in Outlook PST files.
  • To reduce the size of PST files, there is no need to install the Microsoft Outlook application.
  • While reducing the size of Outlook PST files, the application retains all the content and meta properties.
  • With this software, it is also possible to remove header information from Outlook PST files to reduce its size.
  • This PST Compressor Software successfully supports all the latest and earliest versions of Windows OS.
  • With this software, you can reduce the size of multiple PST files in bulk to save valuable time.
  • There are no file size limitations. You can compress large PST files from Outlook without facing any issues.

Common FAQs

Q: Is it possible to compress PST files online?

Yes, it is possible to compress PST files online. Many online solutions available. Only it is recommended to choose any reliable Outlook PST file size reduction solution online.

Q: What are the limitations of compressing Outlook PST files online?

There are several limitations:

  • You cannot bulk compress multiple PST files.
  • No guarantee of accurate compression.
  • Concern for privacy.

Q: Is it safe to use 4n6 software to reduce the size of Outlook PST files?

Yes, it is completely safe to use 4n6 software to compress PST file size. Also, it is highly recommended to use this software if your PST files are very large in size and need to be compressed accurately.

Conclusion

Reducing size of Outlook PST files is not only freeing up valuable space, it’s also important for maintaining fast email performance. By removing attachments, headers, and more, you can reduce the size of your PST files and make them quick to load and open. The recommended software is completely safe. We guarantee you that 4n6 software will give you the safest result. It will only compress the PST file size; the content will remain intact. So, download the software now and start compressing Outlook PST files.