How to Increase Outlook PST File Sizes?

Methods to Increase PST File Sizes in Outlook

Microsoft Outlook is one of the most common email clients. But one factor that remains the center of concern for Outlook users,especially corporate users is the PST size limitation. We all know that Outlook PST and OST file has a size limitation.

The maximum PST and OST file size limitation for Outlook 2010 and above version is 50 GB which was increased from 20 GB. 20 GB is the file size limitation of Outlook 2003 to 2007. And for lower Outlook version,whose use is not prevalent at present is 2 GB.

Users are well aware of PST size limitation but sometimes because of ignorance or unexpected data flow,PST cross its limits. In this condition,its work gets adversely affected and if ignored,the file might get corrupt as well.

PST File Size Reference Tables

Here is the table that represents the size of Outlook PST File:

Outlook 2013 and Above Version

Outlook 2003 to 2007

How to Increase the Size of PST File

A user can increase the PST size using the registry value. The Registry can be increased or decreased to change the overall size of the PST file. However,this method will not work with ANSI Outlook file i.e. Outlook 97 or lower version.

How to Change Outlook PST Size Via the Registry

To increase maximum size PST and OST,the users have to create and set 2 values in the Registry at the given location:

For Outlook 2010

For Outlook 2013

For Outlook 2016

For the successful implementation of the process,the given DWORD values create or set for Non-Unicode PST/OST files:

• MaxFileSize
• WarnFileSize

To execute the process successfully,the following 2 new DWORD values create or set for UNICODE PST/OST files:

• WarnLargeFileSize
• MaxLargeFileSize

Click on MaxLargeFileSize,change the Base setting from Hexadecimal to Decimal,and input the desired new maximum size limit in Megabytes (MB):

• To set a 75 GBlimit,enter:76800
• To set a 100 GBlimit,enter:102400

Click on WarnLargeFileSize,switch the Base setting to Decimal,and enter a value that is lower than maximum size to allow for proper system warnings:

• For a 75 GB limit (warning at 71.25 GB),enter:72960
• For a 100 GB limit (warning at 95 GB),enter:97280

To keep the PST working without hiccups,it is advised that users should keep the difference between Warn Large File Size and Max Large File Size minimum 5%. This gap will help in retrieving data if corruption happens in PST because of the oversize issue.

Registry editor showing MaxLargeFileSize set to 105 GB with the warning at 98 GB

You can understand this better with this example. In this PST,the maximum limit has been set to 105 GB. To increase the maximum size of Outlook PST and OST,the user has to set 2 values in the given location.

Other Available Options to Increase the PST Size

For increasing the PST and OST size,the aforementioned method is correct and it is one of the best methods. But if your main concern is oversized files that adversely affect PST working or leading to corruption in the file;then the other option that you have is splitting or compressing the PST. The professional tools are the best way to split PST Files according to the requirement. In addition to compressing the PST,the software helps in reducing the size of PST significantly without any concern.

The changing registry files can provide a temporary quick-fix,it introduces severe performance slowdowns and massive file corruption risks over time. The safest,modern approach to managing oversized databases is using dedicated Softaken utilities:

• Softaken Split PST Pro:This application safely splits large or oversized UNICODE PST files into multiple smaller,highly manageable pieces by size,year,or folder without risking database structural integrity.
• Softaken Compress PST Pro:This utility optimizes your mailbox layout by completely removing unused space,stripping out heavy attachment files,and compressing your current PST files down to lightning-fast operational speeds.