How to Increase PST File Size in Outlook? Complete Guide

Published By Jamie Kaler

Approved By Rollins Duke

Published On October 5th, 2023

Reading Time 7 Min Read

Are you also receiving errors while opening your Outlook profile, or your PST file has reached the maximum size? If yes, then don’t worry this write-up will explain the safest techniques to increase PST file size in Outlook 2021, 2019, 2016, 2013, 2010, and all previous versions.

We used Outlook profiles personally as well as professionally to store our important data including emails, contacts, calendars, notes, journals, etc. But increasing Outlook PST file is the most common problem with Outlook data files. And because of the large size, there are many errors and problems that users face including:

Your Outlook email client becomes slower and unresponsive, searching, opening, and moving emails may take a long time.
If your PST file has increased, then there is a high risk of data loss and inaccessible and corrupted PST files.
Also, taking a backup of Outlook profile data may take a long time, and also large size of PST files will take unnecessary storage space.

Cause whatever, you will get the right solution here for your all questions and queries with complete information.

Maximum PST Size in Outlook 2021, 2019, 2016, and All Versions

All versions of Outlook 2021, 2019, 2016, 2013, 2010, 2007, 2003, 2002, and 1997 supports ANSI and UNICODE PST file. And all PST files have different file sizes, depending on the Outlook versions. Before starting the process to increase PST file size in Outlook, let’s have a look at the PST size limit for different Outlook versions.

Outlook Version	PST File Size Limit
Outlook 97 – 2002	2 GB
Outlook 2003 and 2007	20 GB
Outlook 2010, 2013, 2016, 2019, and 2021	50 GB

Here is the complete information on the maximum recommended size of PST file by Microsoft.

Outlook 2010, 2013, 2016, 2019, and 2021

Name	Type	Valid Data Range	Default
MaxLargeFileSize	REG_DWORD	0x00000001 – 0x0000C800	0x0000C800 51,200 (50 GB)
WarnLargeFileSize	REG_DWORD	0x00000000 – 0x0000BE00	0x0000BE00 48,640 (47.5 GB)
MaxFileSize	REG_DWORD	0x001F4400 – 0x7C004400	0x7BB04400 2,075,149,312 (1.933 GB)
WarnFileSize	REG_DWORD	0x00042400 – 0x7C004400	0x74404400 1,950,368,768 (1.816 GB)

Outlook 2003 and 2007

Name	Type	Valid Data Range	Default
MaxLargeFileSize	REG_DWORD	0x00000001 – 0x0000C800	0x00005000 20,480 (20 GB)
WarnLargeFileSize	REG_DWORD	0x00000000 – 0x0000BE00	0x00004C00 19,456 (19 GB)
MaxFileSize	REG_DWORD	0x001F4400 – 0x7C004400	0x7BB04400 2,075,149,312 (1.933 GB)
WarnFileSize	REG_DWORD	0x00042400 – 0x7C004400	0x74404400 1,950,368,768 (1.816 GB)

Why Users Should Not Increase PST File Size in Outlook?

If you want to increase Outlook mailbox size, then I just to inform you to do this task will lose your data completely or highly corrupt your PST file. Users can maximize the size of the PST file approx. 4GB by modifying or adding the value of registry entries. Below we have explained everything about registry entry.x`.

Information About Registry Entries to Increase Outlook Mailbox Size

You can increase PST file size in Outlook by editing these registry entries. All four registry entries are explained here in detail to adjust the limits.

MaxLargeFileSize: its limits the extent that the Outlook PST file can grow. Outlook will restrict expanding the size when the file has reached the maximum size.
MaxFileSize: This registry applies only to the ANSI (American National Standards Institute) PST file.
WarnLargeFileSize: It set the maximum file size for the PST file, when your data file reaches the limit users can’t add more data.
WarnFileSize: Similar to WarnLargeFileSize, it is only used for ANSI PST files.

How to Use Entries to Increase PST file size in Outlook?

After having complete information about Outlook registry entries, now have a look at the registry path, which will help in the process to accomplish the task.

For Outlook 2003

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\11.0\Outlook\PST

MS Outlook 2007

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\12.0\Outlook\PST

For Outlook 2010

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\14.0\Outlook\PST

MS Outlook 2013

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\15.0\Outlook\PST

For Outlook 2016

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\PST

How to Increase Mailbox Size in Outlook Using Regedit?

Open RUN by clicking on the Win+R key and typing the “Regedit” >> “OK” icon.
Look for the “Registry Editor” >> HKEY_CURRENT_USER key.
Now expand the folder and go for Software >> Policies >> Microsoft >> Office >> Outlook >> and PST folders.
In the PST folder, you will find all the registries and right-click on the registry that associates with your Outlook account.
Choose the “Modify” icon and enter the desired value in the “Value Data Box” and hit the OK button.

Important Note: If your registry value has not been added already then you have to configure it by going PST >> New >> DWORD Value.

Why You Should Not Use Manual Methods?

There are some limitations, which can cause data loss, corruption, etc. All the considerations are mentioned below in detail:

Data Loss: This manual method required technical expertise and accuracy; one mistake will lead to your data loss permanently.
Corruption: It is very important to maintain at least a 5% difference between Warn Large File Size and Max Large File Size because oversize files can corrupt your data.
Outlook Performance: If you had increase PST file size in Outlook then your Outlook become slower and unresponsive.

Professional Method to Solve Increase PST File Size in Outlook Error

As we have explained everything, why users should not increase Outlook mailbox size due to end number or problems and limitations. So, Instead of increasing, you can split Outlook PST files into smaller parts without having trouble.

Also, the split files are easier to manage, and avoid all the problems that you have been facing in your Outlook account. For breaking the PST file, we are going to use one of the best and safest RecoveryTools PST Splitter Tool tools to accomplish this task.

The software comes with amazing and advanced features, that can easily resolve the increase PST file size in Outlook errors in just a few clicks. The software comes with a free demo version so that users can easily analyze the software’s performance and the features of how its works. To know more about the software read the features and working steps that are mentioned below:

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Working Steps to Resolve to Increase Outlook Mailbox Size Error

Download the software on your system.
Add the PST file automatically using the “Convert Configured Outlook Mailbox Data” option or add manually using the “Select Files” and “Select Folders” options.
Enable the “Use Recovery Mode” option for damaged, corrupted, and inaccessible PST files and click on the Next button.
Enable the required folders and subfolders and hit the Next button.
The software will choose the desktop location by default, to change the location use the Browse button.
Enable the required Split Option as per your need.
And apply the filters from the Advanced Split Option tab.
Lastly, hit the Split button to resolve the increase PST file size in Outlook error.

Time to Say Goodbye

Here we have explained the complete procedure, precautions, and limitations to increase PST file size in Outlook 2021, 2019, 2016, 2013, 2010, and all previous versions. Increasing the Outlook mailbox size process is not the right way to resolve your issues. Because if you have increased the size, then you will more errors in Outlook. So, dividing your Outlook data file PST is the right way to solve your all problems. To accomplish this task, we have mentioned the best way to do it, which comes with amazing and advanced features. I have tried my best to provide the complete information to solve increase Outlook mailbox size error, I hope you find the article helpful.