How to Deal with Too Large PST File

This essay explores various solutions and recommendations for effectively managing a large PST file to optimize Outlook performance and prevent data loss.

Nene Aly

By Nene Aly / Updated on March 4, 2024

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A large PST file in Outlook can lead to slow performance, crashes, and the potential for data loss. In this essay, we will discuss the causes of large PST files and provide useful solutions and software recommendations to effectively manage file size and improve Outlook performance.

Problem: Large PST File

A large PST file is a common problem for Outlook users, causing sluggish performance, crashes, and difficulties in accessing email data. There are several reasons why a PST file may become too large.

1. Accumulation of emails and attachments over time without proper organization and management.

2. Frequent use of Outlook's AutoArchive feature without proper configuration.

3. Lack of regular maintenance, such as compacting the file to remove unused space.

Solution 1: Reduce PST File Size

To reduce the size of a large PST file, follow these steps:

  1. Open Outlook and go to the File tab.
  2. Click on Account Settings and select Account Settings from the drop-down menu.
  3. In the Account Settings window, select the Data Files tab.
  4. Select the large PST file and click on Settings.
  5. In the resulting window, click on the Compact Now button to remove unused space from the file.

Solution 2: Archive Old Emails

Archiving old emails is an effective way to manage a large PST file. Follow these steps to archive emails in Outlook:

  1. Open Outlook and go to the File tab.
  2. Click on Options and select Advanced from the left sidebar.
  3. In the AutoArchive section, click on AutoArchive Settings.
  4. Configure the desired settings for auto-archiving old emails, such as the frequency and location of the archive file.
  5. Click OK to save the changes.

Solution 3: Split PST File

If the above solutions are not sufficient, splitting the PST file into smaller, more manageable parts can help. Follow these steps to split a large PST file:

  1. Download and install a reputable PST file splitting software, such as Stellar PST Splitter.
  2. Run the software and select the large PST file to be split.
  3. Choose the splitting criteria, such as file size or date.
  4. Specify the save location for the split files and click Split.
  5. Wait for the process to complete, and then access the smaller PST files.

Software Recommendation: Stellar PST Splitter is a reliable software for splitting large PST files. It offers various splitting options, such as splitting by size or date, and ensures data integrity during the splitting process.

FAQ (Frequently Asked Questions)

Q: How can I check the size of my PST file in Outlook?

A: To check the size of your PST file, open Outlook and navigate to the File tab. Click on Account Settings and select Account Settings from the drop-down menu. In the Account Settings window, select the Data Files tab and look for the file size next to the PST file name.

Q: Can I delete emails directly from the PST file?

A: No, it is not recommended to delete emails directly from the PST file. Use Outlook's built-in features to delete or archive emails to ensure data integrity and proper organization.

Q: How often should I compact my PST file?

A: Compacting the PST file once every few months is recommended to remove unused space and improve performance. However, avoid frequent compaction, as it may lead to file fragmentation.

Q: Is it possible to combine split PST files later?

A: Yes, you can combine split PST files later by using Outlook's Import feature. Simply open Outlook, go to the File tab, click on Open & Export, and choose Import/Export. Follow the on-screen instructions to import the split PST files into a single file.

Q: Are there any free software options for splitting PST files?

A: Yes, there are free software options available for splitting PST files, such as SysTools Split PST and KDETools PST Splitter. However, it is important to research and choose a reliable software that ensures data integrity during the splitting process.

Q: Can I access archived emails after archiving them?

A: Yes, you can access archived emails by navigating to the Archive folder in Outlook. Simply expand the Archive folder in the left sidebar to view the archived emails.


In conclusion, effectively managing a large PST file is crucial for optimizing Outlook performance and preventing data loss. By following the solutions and recommendations provided in this essay, users can successfully reduce the size of the PST file, archive old emails, and split the file if necessary. Additionally, the recommended software, Stellar PST Splitter, offers a reliable solution for splitting large PST files while ensuring data integrity. By implementing these steps and considering the best practices, users can maintain a well-organized Outlook mailbox and enhance overall productivity.

Nene Aly
Nene Aly · Editor