How to Compact PST file in MS Outlook 2016/2013/2010

Deleting redundant and unusable emails regularly is always good to keep a check on PST file size, but this is not enough. Reducing the size of PST file, using the mailbox cleanup tool, and compacting the PST file are also essential measures in this regard. In fact, it is crucial to employ these techniques to reduce the PST size because once the PST file-size reaches its threshold limit, it starts interfering with the normal functioning of Microsoft Outlook and in extreme cases, and the oversized PST file may cause corruption errors in this Outlook-database file.   

When the daily communication including sending and receiving emails, calendar updates, routine and vital tasks, journals, etc. make a regular entry in Outlook then the outcome is ‘oversized PST’ in due course of time. Taking suggested measures to keep the Microsoft Outlook database file-size in check is always useful, but as the data grows, the conventional methods may not be as successful. At some point, the increased size of Personal Storage File or PST starts to interrupt the functioning of Outlook and users may have to take help of a software-based solution to compact the size of PST file.

Why compact PST file? And how does Compacting help?

The need to compact the PST file arises when the oversized PST file results in one or more of the following Microsoft Outlook issues:

  • Slowness in Microsoft Outlook
  • Corruption errors in Outlook or Outlook PST file
  • Performance issues in Outlook
  • Outlook not responding on opening

The compacting of the PST file in MS Outlook 2016, 2013, 2010 prevents it from corruption and helps to improve the Outlook performance. 

Methods to Compact Outlook 2016, 2013, 2010 PST File

  1. Manual Methods:
    a. Use Compact Now’ option in Outlook
    b. Use Mailbox Cleanup tool
    c. Archive old emails in PST
  2. Software Method to compact PST
  1. Manual Methods:

A concise list of steps for all the manual methods – ‘Compact Now’, ‘Mailbox Cleanup tool’ and ‘Archive Old Emails’ are as follows:

In Microsoft Outlook 2016, 2013, 2010, users can archive their mail items online, either automatically or manually, as required.

Compacting the PST file with the help of the manual method is easy, but these methods have limitations like these are not viable to compact large PST files. Moreover, these methods can only work to compact the PST file until the time it has not reached its threshold limit.

  • Software method to Compact PST

A software such as Stellar Toolkit for Outlook manages and optimizes Outlook database files. The software helps the users to compact PST files and enables the following:

  • Extracts attachments in a new or separate folder
  • Compacts all attachments as new PST file
  • Facilitates automated compaction
  • Removes all attachments and save as new PST file
  • The software also allows users to split the PST files as per size, date and email ID.

And if in case the PST file gets corrupt then the toolkit helps repair the corrupt PST and removes further chances of PST file corruption.

free download


Most PST files should be compacted regularly. Even the Outlook Administrators suggest this, but users often fail to do so. The online archiving has helped users to compact PST file in MS Outlook, but this facility is limited to the latest versions. However, online archiving is not the ultimate solution when the PST file-size grows beyond the threshold limit. With Microsoft utilities facing limitations to compact the size of overgrown PST, all that is required is install software such as Stellar Toolkit for Outlook. The software compacts the PST file in MS Outlook 2019, 2016, 2013, 2010 and earlier versions and also helps manage the PST with its wide range of functionality. Along with the Compact feature, the toolkit has various advanced software to deal with Outlook Data file i.e. Repair PST, Split and Merge PST, Convert OST to PST, Compact PST, deleted email recovery, Outlook duplicated remover and PST Password Recovery.

  1. Eric D Wark February 26, 2020
    • Eric Simson March 12, 2020
  2. Eric Simson January 14, 2021

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