Personal Storage Table

The Personal Store (PST ) of the e- mail program Microsoft Outlook for Windows is a proprietary container file that is stored in the tasks, notes, e- mails and calendar.


In addition to a standard file Outlook can manage any number of other PST files. For a backup copy of the PST files can be created. More Outlook data outside the PST files ( eg e- mail accounts, signatures, program settings, etc. ) are managed, but are not considered here.

The maximum size of this file type was 2 GB for the Windows versions of Outlook, Outlook 97 to Outlook 2002.

The format of Outlook PST file has changed with the version of Outlook 2003. From Outlook 2003 Unicode PST file is used, the memory size is 20 GB. After changing a key in the Windows registry database this size can once again be limited.

Import and Export

While Entourage could not handle PST files, Outlook for Mac 2011 can import only Unicode PST files older ANSI PST files of Outlook 2002 and earlier can not be imported. The export of an OLM file, the container format of Outlook for Mac, in a PST file, however, is not possible.

The format can only be exported to Windows in other mail programs, if Outlook is also installed ( using MAPI). Alternatively, there is the libpst library, an application which is the command line program readpst, which is able to read the format.

A common use of PST files as groupware is not possible with Outlook. The Groupware for Outlook is the Microsoft Exchange Server. There are few alternatives to Exchange servers that function based on crosslinked PST files as the MAPI server, such as public share folder or OLfolders.