Stellar Knowledge Base

What is maximum PST size limit for different versions of MS Outlook?

 Modified on: February 15, 2021 |    88157 views

When you add or set up a POP email account in Microsoft Outlook, it stores all the data in single Outlook data file, known as Personal Storage Table (.PST). It is also referred to as a Personal Folder file.
In other words, it is a data file used for the storage of Outlook email objects, such as contacts, attachments, appointments, journals, tasks, events, etc. Each version of Outlook has a different format. These formats are of two types - ANSI and UNICODE. Outlook 2002 and earlier versions use American National Standards Institute (ANSI) format, whereas later versions of Outlook employ the UNICODE format.
Along with different formats, Microsoft has also set different Outlook .PST file size limits. Once the set PST file size limit reaches or exceeds, no more data can be saved in the PST file.

Outlook .PST File Size Limits for Different Versions

  • Outlook 2002 and prior versions of Outlook allow you to store data only up to 2 GB.
  • Outlook 2003 and 2007 have a size limit of 20 GB.
  • Outlook 2010, Outlook 2013, and Outlook 2016 has file size limit up to 50 GB.

When the Outlook PST file approaches the set maximum PST file size limit set by the administrator, it fails to add/store more data. As a result, Outlook starts behaving abruptly, and users often experience performance issues.

A large-sized PST may also turn inaccessible or corrupt due to inconsistencies and integrity issues that can lead to data loss. Therefore, it is always advisable not to store unwanted Outlook email objects in a .PST file.

However, if the PST file gets damaged/corrupt due to large-size, you can use Stellar Repair for Outlook to repair the file and save the mail items in a new PST file. Besides, if the original or repaired PST file size is large, you can use the Compact and Save or Split and Save feature in Stellar Repair for Outlook to significantly compress and reduce PST file size. By using this pst repair software, you can greatly minimize the risk of PST corruption and avoid data loss.


Further, you may also choose to increase or decrease the Outlook PST file size limit by applying changes or editing the following registry entries in Windows.

1. MaxLargeFileSize  and WarnLargeFileSize

This registry is used to set the maximum allowable data for the UNICODE Outlook PST file. You can set a maximum of 20 GB PST file size limit for Outlook 2007 and 2003 or a 50 GB PST size limit in Outlook 2010 and later versions. 

2. MaxFileSize and WarnFileSize

These registry key entries work similar to MaxLargeFileSize and WarnLargeFileSize registries but for ANSI formatted PST files with a PST size limit of 2 GB for Outlook 2002 and earlier versions.




Note: You can create a .PST registry key if it does not exist under HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook. Then create MaxLargeFileSize and WarnLargeFileSize (DWORD 32-bit) values manually. You can then define the size limit in the Value data field (refer to the screenshot).

Though you can increase the PST file size limit, it is not recommended to increase the Outlook .PST file limit to more than 100 GB to avoid performance issues and corruption.


5 User Comments

Are you saying that your .olm to pst converter will convert any file <50 GB?
Outlook Mac 2011 to Outlook Windows 2013 is what I plan to do.
I intend to purchase your tool and am unsure if the tool will convert all 25 GB of my data mail and contacts/calenders



Hi Rohit,

Yes, there is no file size limitation to use OLM to PST converter tool. This tool can convert almost any amount of data including mails, calendars, contacts etc. from OLM to PST file type.

You can surely convert all your mail data from Outlook Mac 2011 to Outlook Windows 2013.

Glad to address in case you've any further queries.


Amit Pandey

how much size PST import in office 365 (MAC BOOk Air)



Hi? What is the maximum size of the PST file that your software (v support for Windows 10 Home ?
How long it takes to analyse the PST file (47Go size), I run your software for 6 hours it was still analysing ?
Thank you.
P Andrei






There is no size limitation in our software for PST.

Scanning time depends on a lot of factors like capacity of the drive, severity of corruption etc. Therefore we can’t give you an estimate about the scanning time.

As long as the software is not getting stuck during scan, we suggest you to kindly continue with the scan and check results.

For more help, please submit ticket using below link.


Stellar Data Recovery


User Comments




Stellar Repair for OutlookStellar Repair for Outlook scans the corrupt PST file and repairs and restores all mailbox contents. The repaired email items are saved as new usable PST file which can imported in MS Outlook.

Learn More red arrow


Related Articles



Why Choose Stellar?

  • 0M+


  • 0+

    Years of Excellence

  • 0+

    R&D Engineers

  • 0+


  • 0+


  • 0+

    Awards Received