How to increase the maximum size for PST and OST files in Outlook

Outlook PST Repair /December 23, 2024

Microsoft Outlook is one of the most popular email clients today, and millions of people and companies use it. Over time, when users increase the number of emails, attachments, and other data, Outlook’s data files – PST for POP3/IMAP accounts and OST for Exchange accounts – may become too large. When this occurs, it can cause poor performance, inability to send/receive new emails, and, in some cases, data corruption. In this article, you will learn how PST and OST files grow large and how to raise the size limits in Outlook.

Reasons for Reaching Size Limits

If PST and OST files grow to their maximum size or become even closer to it, they can become an issue. Several factors contribute to this:

  • Accumulation of emails: In the long run, users have numerous emails, including those they receive and are not usually deleted after some time.
  • Large attachments: Large file attachments in emails also tend to fill up PST/OST files more quickly than other activities.
  • Calendar entries and contacts: Outlook’s calendar and contacts also contribute to the size of the overall package.
  • Journal entries: To the users who use the journaling feature of Outlook, these entries add to the size of the files.
  • Default size limits: Outlook versions before Outlook 2010 are found to have lower default size limits for PST/OST files.

Methods to Increase the Maximum Size for PST-files and OST-files in Outlook

Method 1: Modifying the Windows Registry

This method involves using the Windows Registry to change the PST/OST file size limit in size. Although it is quite effective, it should be used appropriately since wrong changes to the Registry may lead to system instability. Before you proceed with the next steps, it is advisable to backup the Registry.

  1. Close Outlook completely.
  2. Press the Windows key on your keyboard and hold it while pressing the ‘R’ key.
  3. One must enter the “regedit” command in the command line and press “Enter” to launch the Registry Editor.
  4. Go to the following key, which depends on the version of Outlook you have installed.
      ● Outlook 2019/2016: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\PST
      ● Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\PST
      ● Outlook 2010: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\PST

  5. Again, right-click on the right pane, click on New, and then click on DWORD (32-bit) Value.
  6. Give the new value the name “MaxLargeFileSize” (quotes included).
  7. Double-click the new value and set the Value data to the numeric value of the maximum size in MBs for instance, 51200 for 50 GB.
  8. Make another DWORD value called “WarnLargeFileSize” and set it to another figure, a bit lower than the previous one.
  9. Click ‘OK’ to close the Registry Editor and start the Outlook application again.

Method 2:Using Group Policy (for organizations)

The Group Policy method is suitable for organizations that have many Outlook users in their facilities. It enables the administrators to manage the PST file size policy in the organization from the central point. However, this method involves administrative access and cannot be used for a single user or home use.

  • Right-click on the Group Policy Management Console.
  • Create or modify a GPO.
  • They can visit the User Configuration > Administrative Templates > Microsoft Outlook > Miscellaneous > PST Setting.
  • Large PST Absolute Maximum Size and Large PST Warn About Maximum Size should be set up.
  • This is done by clicking on the Group Policy and selecting the option ‘apply’.

    • Method 3: Compact PST files

    The PST file compacting is the function integrated into Outlook that can help manage the size of the PST file, and this will not be possible if no changes are made to the PST file. It is a safe method that helps reduce the unneeded space between PST files. Nevertheless, it may not be good enough for users already at the maximum file size limit or even beyond it.

    Although it does not directly contribute to the increase of the size limit, it can help to reduce the size of the PST files:

    1. In Outlook, please click File, then Account Settings, then Account Settings.
    2. Go to the Data Files tab.
    3. Find the PST file you want to compact, right-click, and click on settings.
    4. In the new window, click the Compact Now button.

    Method 4: Automated Goldy Outlook PST Repair Tool

    There is no better way to increase the maximum size for PST and OST than by using the above-described method. But if your focus concern is over-sized files, which can inversely impact working or cause corruption, you can split or compress PST.

    With the professional way, users can split PST files according to their requirements, compress PST files and decrease their size without any problem to overcome the problem of large PST.

    Goldy Outlook PST Repair Tool is designed to manage large PST files easily, so you do not have to spend time fixing Outlook problems. This is especially useful when the other recovery methods do not work or when working with highly damaged PST files. Download it and use its trial version to know whether the tool is functioning.

    Conclusion

    It is necessary to raise the maximum PST and OST size in Outlook for effective email functioning, particularly for users with numerous emails and attachments. There are, however, manual approaches to it, but they are tedious and may involve a lot of steps. The Goldy Outlook PST Repair Tool is a single package that can handle large PST files, fix corruptions and restore lost data. This way, the user can save time and avoid data loss, and Outlook will remain convenient and fast.

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