Microsoft Outlook Personal Folders (ANSI)

Summary

Name

Microsoft Outlook Personal Folders (ANSI)

Version

1997-2002

Identifiers

• MIME: application/vnd.ms-outlook
• Library of Congress Format Description Identifier: fdd000377
• PUID: x-fmt/248

Description

The Personal Folders File or PST is an open proprietary data file format used to store local copies of messages, calendar events, and other items within Microsoft software including Microsoft Office Outlook. PST files are used to store archived items and to maintain offline availability of the items. PST is a stand-alone, self-contained, structured binary file format that does not require any external dependencies. Each PST file represents a message store that contains an arbitrary hierarchy of Folder objects, which contains Message objects, which can contain Attachment objects. Information about Folder objects, Message objects, and Attachment objects are stored in properties, which collectively contain all of the information about the particular item. Now considered a legacy format and replaced by PST_Unicode, PST_ANSI was used by Microsoft Outlook 97-2002. It employs the American National Standards Institute (ANSI) character set and has an overall size limit of 2 gigabytes (GB). PST_ANSI uses 32-bit values to represent block IDs (BIDs) and byte index (IB).

Note

https://www.loc.gov/preservation/digital/formats/fdd/fdd000377.shtml; Format details: http://msdn.microsoft.com/en-us/library/ff385210%28v=office.12%29.aspx . Format specification from Microsoft that covers both PST_ANSI and PST_Unicode files; MIME Type: appears in Forensic Wiki's page on Personal Folder File (PAB, PST, OST)

File extensions

pst

Source

Digital Preservation Department / The National Archives

Internal signatures

Changelog

• Updated in V120

  Release date

  25 February 2025

  Microsoft Outlook Personal File (ANSI) 1997-2002: New description, MIME Type, library of congress fdd identifier and notes added. Submitted by Library of Congress.