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How to Compact PST File without Opening Outlook?

Published By Jamie Kaler 
Rollins Duke
Approved By Rollins Duke
Published On October 5th, 2023
Reading Time 5 Min Read

Deleting unwanted emails to compact PST file without opening Outlook or reduce Outlook mailbox size without Outlook. You have to compress PST file to resolve your problems.

We all know that Outlook creates PST files to store emails, contacts, calendars, notes, journals, etc. But when your Outlook PST file has reached its maximum size, it occurs multiple problems in Outlook such as your Outlook becoming slow and unresponsive, and also oversized PST file is the main reason for corruption, due to which you can lose your data.

Cause whatever, here you will get the complete information with a step-by-step guide to compact PST file without opening Outlook.

How to Compress PST Files of Outlook 2021, 2019, 2016, & All Versions?

Here first we are going to use the professional method to compact PST file without opening Outlook using RecoveryTools PST Splitter Tool. Because compacting, and compressing are not enough to reduce the file size. So, we have to split Outlook PST file into smaller parts for flawless performance.

We choose this software because it’s highly recommended software in the market to accomplish this task. Because it comes with advanced algorithms, that makes the software more powerful than the other software.

It comes with a very simple and easy-to-use interface for all technical and non-technical users. also, users can download the free demo version for free to split 25 emails from each PST folder. All the advanced features and step-by-step guide are mentioned below:

Steps to Compact PST Files without Opening Outlook

  1. Download the software.

    tool to Compact PST Files without Opening Outlook

  2. Add the PST file automatically and manually.

    Add the PST file

  3. Enable Use Recovery Mode for corrupt files.

    Use Recovery Mode

  4. Select the required folders/subfolder as per your need.

    Select the required folders

  5. Browse the location to save your resultant data.


  6. Enable Advanced features from the Split Options tab.

    Advanced features

  7. Hit the Split button to compact PST file without opening Outlook.

    compact PST file without opening Outlook

Why Users Should Use Expert Tool Over Manual Methods?

You should use the expert solution over manual methods because it comes with advanced and phenomenal features. Some of them are mentioned below:

  • The software allows users to break PST files into 2 GB, 5 GB, 10 GB, and 20 GB sizes.
  • It supports all types of PST files including corrupted, damaged, inaccessible, and orphan PST files.
  • Also, the software can easily load the data from the default storage location, whether your Outlook profile is working or not.
  • Users can easily break multiple Outlook files in bulk to compact PST file without opening Outlook accounts.
  • Also, it offers features to create separate PST per user, such as: If you have 10 PST files, then by enabling this option it will generate 10 PST files for each file.

Here we have discussed expert tools to compact PST file without opening Outlook with features. Now we will mention all the manual methods to compress PST files.

How to Compress PST Files in Outlook 2021, 2019, and 2016 Manually?

Outlook provides a Compact Now feature, that helps users to shrink PST files. Here we will explain all the manual methods with Compact Now utility method. All the methods with limitations are mentioned below:

Method 1: Compact PST File using “Compact Now” Utility

  1. Open Outlook email client.
  2. Hit on the File >> Info tab from the list.
  3. Select Account Settings >> Account Setting… option.

    Account Setting

  4. Click on the Data Files tab.

    Data Files

  5. Choose the PST file for compact.

    Choose the PST file

  6. And compacting PST file process will start.

    compacting PST file

Method 2: By Archiving PST File

  1. Open Outlook on your system.
  2. Click on the File >> Info tab.
  3. Choose Tools >> Clean Up Old Items option.

    Tools >> Clean Up Old Items

  4. Enable the “Archive this Folder and all Subfolders” option.
  5. Check the “Include items with the Do not Auto Archive” option.

    Include items with the Do not Auto Archive

  6. Lastly, click on the OK button to compact PST file without opening Outlook in Outlook.

As you can see, manual methods are so simple and straightforward. But manual methods have some limitations such as:

  • Outlook must be installed on your system.
  • Also, your Outlook must be in working condition.
  • It does not support corrupted, damaged, and inaccessible PST files.
  • No filter is available to compact PST files without opening Outlook.

Frequently Asked Questions

  • What does compacting an Outlook PST File do?

    Ans: –Compacting Outlook PST file process reclaims that space that is unavailable due to being occupied by an item. It helps to reduce the data file size and increase PST file size in Outlook.

  • Does Outlook automatically Create PST files?

    Ans: – Yes, when you set up the Outlook account on your system, it automatically creates a PST file that is connected to the created account.

  • What is the maximum size of Outlook PST file?

    Ans: –The size of Outlook PST file depends on the version, Outlook 98 and 2002 creates a 2 GB file size, Outlook 2003 and 2007 support a 20 GB limit, and all the latest version of Outlook 2021, 2019, 2016, 2013, and 2010 creates a 50 GB size limit of PST file.

  • Is it safe to delete Outlook PST file?

    Ans: – Yes, if you have unwanted emails in PST files, and you want to compact PST file without opening Outlook, then you should delete them. And if you don’t want to delete anything, then you should split your file using the expert tool.

Time to Say Goodbye

Here we have explained the methods to compact PST file without opening Outlook using manual methods and expert tools. First, we have mentioned an expert tool with all advanced features and working steps. Also, if you have any doubt about the software then you can download the free version of it before investing your money. And then we have explained manual methods, which have limitations. So, choose the methods that suit your needs best. I hope this article had beneficial for you.