How to Fix Error "Outlook.pst has reached its maximum size.”

Personal Storage Table or PST, also known as Personal Folders, is an Outlook data file that stores mail items, such as messages, contacts, attachments, tasks, calendar items, etc. Outlook creates a PST file on the local drive when you add a POP (POP3) account, such as Gmail, Hotmail, etc. 

By default, Microsoft Outlook 2003 supports American National Standards Institute (ANSI) .pst files, while Outlook 2007, 2010, 2013, 2016, and 2019 supports both ANSI and UNICODE personal folders or .pst files.

The recommended limit for ANSI and UNICODE .pst files are 20GB and 50GB, respectively.

With time and as you receive more emails and attachments, the PST file size may grow larger and exceed the recommended limit set by the administrator via Group Policies.

When .pst File exceeds either the recommended file size or a limit set by the administrator, you may encounter the following error message while accessing your Outlook account.

You can check your PST mailbox size in Outlook via File> Info.

The error may also occur if the PST file is unreadable, corrupt, or damaged due to large size or other factors, such as abrupt shutdown or system crash, malware or virus intrusion, etc.

As a result, you cannot send or receive new emails. Thus, it's critical to fix Outlook.pst has reached its maximum size issue asap.

In this article, we have shared some simple and easy to follow methods that you can use to either increase the PST file size limit manually or offload the mail items from your Outlook PST file to new multiple PST files to free up space in the File.   

Methods to Fix Outlook.pst Has Reached Its Maximum Size Issue

If you read the complete error, it suggests that you empty your deleted items folder or delete messages from your mailbox to create more space for new emails. However, as mentioned earlier, you may also increase the PST file size limit by editing the Outlook registry keys on your system or asking your administrator to increase the PST file size limit via Group Policies.

Below we have discussed these methods in detail to help you fix Outlook.pst has reached its maximum size error in Outlook for Windows.

Method 1: Empty PST File to Create More Space

You can empty a PST file to create more space for new emails by either emptying Deleted Items folder or archiving older or large emails to a local PST file and then deleting archived emails from your default PST file. The steps are as follow,

To empty Deleted Items Folder,

• In Outlook 203, 2016, or 2019, navigate to File> Info and click Cleanup Tools> Empty Deleted Items Folder.

• Click Yes when prompted.

• This will remove all deleted emails and mail items from your Outlook PST file.

In Outlook 2010 and 2007, right-click on Deleted Items folder and choose Empty Folder to remove deleted mail items and empty PST files.

To archive old emails and then delete them to create free space in Outlook PST file, follow these steps,

• In Outlook 2013, 2016 or 2019, go to File> Info and click Tools> Clean Up Old Items… or Cleanup Tools> Archive.

• In Outlook 2010, click File> Cleanup Tools> Archive.
• In Outlook 2007, click File> Archive
• Select the folders to archive emails from and choose the date from the Archive items older than.

• Then click Browse to choose a location to save the archived emails and click
• This will archive all emails older than the date you chose in a local PST file at your desired location. You open this local PST file in your Outlook and access archived mail items.
• Now you can delete the archived emails older than the date you selected to create space in the default PST file and resolve the pst has reached its maximum size error.

Method 2: Increase PST File Size Via Registry Editor

By creating or editing the MaxFileSize, WarnFileSize, MaxLargeFileSize, and WarnLargeFileSize registry entries on your Windows PC, you can change or limit the PST file size.

These registry entries are located at the following locations,

• Outlook 2003: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\11.0\Outlook\PST
• Outlook 2007: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook\PST
• Outlook 2010: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\PST
• Outlook 2013: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\PST
• Outlook 2016: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\PST
• Outlook 2019: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\PST

To change the PST file size limit, follow these steps,

• Press Windows+R, type regedit.exe, and press the 'Enter' key or click 'OK.'

• Navigate to the registry entry by following the above path and then click PST.

• If MaxFileSize, WarnFileSize, MaxLargeFileSize and WarnLargeFileSize registry entries are not present, create them. For this, right-click on the empty space and choose the DWORD (32-bit) value.

• Type the registry entry name as MaxFileSize and then double click on it.

• In the Value data field, type a value in the byte. For instance, 1GB=1024*1024*1024 byte.

• Click 'OK.'
• Repeat these steps to create and enter the value for WarnFileSize, MaxLargeFileSize and WarnLargeFileSize

This will increase the PST file size limit and give you more space in PST to store mail items and resolve the Outlook.pst has reached its maximum size error.

Outlook.pst Has Reached Its Maximum Size Not Resolved

If the Outlook.pst has reached its maximum size error still appears, and you can't send or receive emails; it could be due to a damaged PST file. You can launch SCANPST.EXE located in the Microsoft Office installation directory.

Launch SCANPST.EXE and follow these steps to repair the PST file and fix the Outlook.pst has reached its maximum size error.

• Click Browse to choose the damaged PST file and then click Start.

• The Inbox Repair Tool will scan the corrupt PST file and display an option to repair the file if it finds issues with the File. Click Repair.

• During the repair process, the Inbox Repair Tool may stop responding. So wait for it to finish repairing. After the repair, you will see the following message.

• After the repair, restart Outlook. The error Outlook.pst has reached its maximum size should be fixed now.

IMPORTANT NOTE: SCANPST.EXE can repair minor corruption in PST files up to 2GB size. If the PST file is larger, the tool may crash or fail to repair. Also, SCANPST restores PST files by removing irrecoverable mail items that can lead to data loss.

To Wrap up

If the SCANPST tool crashed or didn't respond after a while, the PST could be severely damaged or corrupt. In such cases, the Inbox Repair tool may fail to fix the PST file corruption due to its limitations.

However, you can use an advanced Outlook PST repair tool to repair severely corrupt, large, or encrypted PST files without any risk of data loss. The software helps you save the mail items extracted from the damaged or corrupt PST file in a new or existing Outlook PST file on your PC.

Further, you can compact or split large PST files into smaller PSTs based on size or date range to prevent PST corruption due to large size or oversizing. You may also export the mail items to Office 365 directly. To get started, download the free demo version and try it yourself to repair the PST file and fix the Outlook.pst has reached its maximum size issue.