364 Microsoft Outlook Personal Folders (ANSI) 1997-2002 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). Text 1 Digital Preservation Department / The National Archives 02 Aug 2005 Digital preservation research.v.120- New description, MIME Type, library of congress fdd identifier and notes added as part of PRONOM Research Week 2024. Submitted by the Library of Congress. 03 Jan 2025 application/vnd.ms-outlook MIME fdd000377 Library of Congress Format Description Identifier x-fmt/248 PUID pst File extension 260 Personal Storage Table *.pst (ANSI) Byte analysis completed in http://downloads.sourceforge.net/libpff/Personal_Foler_File_Format.pdf (Personal Folder File (PFF) File Format Specification) and sequence confirmed by research completed in http://www.five-ten-sg.com/libpst/rn01re06.html. PST file header, 24 bytes in total. 1 Absolute from BOF 0 Little-endian 2142444E{4}534D(0E00|0F00)