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Safe Way to Compact PST File without Opening Outlook

Published By Raj
Debasish Pramanik
Approved By Debasish Pramanik
Published On January 22nd, 2024
Reading Time 6 Minutes Reading
Category MS Outlook

As Outlook users, we know that managing PST files is a challenging task. Due to its performance and advanced functionalities, most users prefer to use MS Outlook. But the general problem with Outlook is related to its data file known as PST (Personal Storage Table) file.

Well the PST file has a certain file size limit as it can only store the mailbox data up to its fixed maximum size. Users should never let the PST file reach its maximum size limit which may cause several severe corruption issues and Outlook performance-related issues. In this blog, we are going to suggest a safe way to compact PST file without opening Outlook.

MS Outlook email client generally saves its PST data files in two formats i.e. ANSI format that is used in Outlook version 1992 to 2002, and Unicode format associated with Outlook 2003 and later versions. ANSI format PST files can store mailbox maximum data of up to 2GB. But, a UNICODE format PST data file provides mailbox storage of 20 GB to 50 GB. Unicode PST files rarely reach their maximum limit, but ANSI PST files easily reach beyond their maximum size limit. Then, go with this write-up and learn the save way to reduce PST file size without Outlook.

Table of Content

Challenges Faced with Oversized PST Files

An oversized PST file may lead to various issues and corruption problems. User needs to compact PST file without opening Outlook because oversized PST file generally affects performance and many more. Some of the major challenges faced by Outlook users after reaching the PST file its maximum size limit are as follows:

Large PST files may corrupt or be damaged easily – When PST files often grow to their maximum, then they become prone to corruption. These issues mostly occur when the data is accessed on the network.

Oversized PST files can be inaccessible – The corruption problem of the PST file leads to the inaccessible stage by showing an error message. The error message can be like “Your PST data file might have exceeded its maximum size limit”.

Generally, Outlook users can delete unwanted email data manually in order to compact Outlook data files. But, in order to compact PST file without opening Outlook there are not many options available.

Reduce PST File Size Without Outlook – 5 Steps

  1. Download & Run the Software.
  2. Select the Add File/ Folder Option.
  3. Select the Compact Option to Reduce to PST Size.
  4. Select the destination location and the Item Type.
  5. At Last, Click on the Next Button to End the Task.

How to Manually Compact PST Files with Outlook?

Step 1: Launch and open the MS Outlook client into the system.

Step 2: Now select and delete unwanted data items from your mailbox.

Step 3: Then, click on the Folder List. Here, right-click on Deleted Items folders, and select Empty Folder.

Step 4: Now, click on File >> Info >> Account Settings.

Step 5: In the Account Settings window, click on Data Files, and select Outlook Data File. Click on the Settings tab.

Step 6: A Personal Folders pop-up box will display, click Compact Now.

Step 7: The process to compact the Outlook data file will start on your computer. Let’s wait until it gets complete.

Sometimes manual tricks fail due to many reasons and do not work. Manual solutions are also time-consuming and sometimes take several hours to execute. In such circumstances, Outlook users can use professional tools to compact PST files without Outlook. 

Professional Way to Compact PST File without Opening Outlook

Outlook users can try a professional solution that takes less time than the manual solution. Use a proficient PST Compress Tool that provides excellent results and does not require any technical expertise. It is an outstanding solution to reduce PST by its Size, Folder, Date, Year, and Email ID.

The software is capable of dividing both ANSI and UNICODE format PST files without any file size limitation. With this safe and secure application, compact Outlook data files with no alteration and modifications to the Original PST files data.

Download Now Purchase Now

Follow the Steps to Reduce PST File Size without Outlook

Step 1: Download and install the PST Compress Software.

reduce pst file size without outlook

Step 2: Choose Add Files or Add Folder option to add the oversized PST file.

reduce pst file size without outlook

Step 3: Select the Compact option that you are going to use for compacting the oversized PST file.

select compact option

Step 4: Choose the Destination Location to save the compact PST file.

reduce pst file size without outlook

Step 5: After this select the Item Type like Mail, Calendar, Task, Contacts, and Journals.

reduce pst file size without outlook

Step 6: At last click on the Next button and once the task is over click on the OK button.

reduce pst file size without outlook

Also Read:- Fix Outlook PST File is Too Large Issue Without Any Data Loss


A large PST file can lead to serious troubles for Outlook users such as severe corruption issues, etc. In this article, we have provided both manual and professional solutions to compact PST file without opening Outlook. For better results, use recommended safe software that enables you to reduce PST file size without Outlook any hassle.

Frequently Asked Questions by the Users

Q. How do I compress a PST file size?
A. To compress the size of a PST file, you can use the manual solution mentioned above if you are a good technical user. But, if you are not from the technical field. Then you should go for the secure automated solution explained in this article.

Q. How do I open a PST file that is too large?
A. To open a PST file that is too large you have to reduce the PST file size. So, to reduce PST file size without Outlook we are having the best software mentioned above.

Q. How can I compact PST file without opening Outlook?
A. You can easily do this task with the help of above mentioned quick 5 steps. These steps help the user to compact PST files without any data loss.

By Raj

A technical analyst and a writer with innovative ideas when it comes to technology. Provides solutions, tips and tricks to get things done using technology.