Increase maximum size pst-files
I heard that the default size for pst-files is 20 GB but also that there must be a registry value that allows to increase the maximum up to approximately 4PB (4096TB).
How do I increase the maximum file size of an UNICODE pst file?
In Outlook 2003 and Outlook 2007, the maximum size of a Unicode pst-file has indeed been limited to 20GB. In Outlook 2010, 2013 and 2016, this limit has been set to 50GB.
You can increase (but also decrease) this limit via the Registry or via Group Policies.
Note: This tip does not apply to pst-files who are in the Outlook 97-2002 format (ANSI formatted pst-files).
Via the Registry
To increase the maximum size of a pst-file in Outlook, you’ll need to create and set 2 values in the following location in the Registry;
- Outlook 2003
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\PST - Outlook 2007
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\PST - Outlook 2010
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\PST - Outlook 2013
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\PST - Outlook 2016
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\PST
The following 2 new DWORD values must be created or set;
WarnLargeFileSize
Don’t set this higher than4090445042(decimal) orf3cf3cf2(hexadecimal)MaxLargeFileSize
Don’t set this higher than4294967295(decimal) orffffffff(hexadecimal)
The first value is how many MB a user can write to a pst-file before receiving a warning that the file is full. The second value is how many MB the system can write to a pst-file. This difference has to be at least 5% since there is more written to a pst-file than just user data.
Above the maximum size of a pst-file has been set to 100GB with a warning at 95GB.
Via Group Policies
Not comfortable editing the Registry? You can then use Group Policies as well even when you are on a home computer. For instructions on how to use Group Policies see this guide.
The settings for adjusting the pst file size can be found in the section Miscellaneous-> PST Settings. The following 2 settings need to be modified;
- Large PST: Absolute maximum size
Don’t set this higher than4294967295 - Large PST: Size to disable adding new content
Don’t set this higher than4090445042




