Personal Folder File

File Format
Name	Personal Folder File
Ontology	Electronic File Formats E-Mail, newsgroups, and forums Personal Folder File
Extension(s)	.pab, .pst, .ost, .nst
MIME Type(s)	application/vnd.ms-outlook
PRONOM	x-fmt/75, x-fmt/248, x-fmt/249

A Personal Folder File is used by Microsoft Outlook to store e-mails and other things. There are three varieties, which exist in 32 and 64 bit varieties:

• Personal Address Book (PAB) - stores contacts/address book entries
• Personal Storage Table (PST) - has mailboxes and other things such as tasks, notes, and appointments
• Offline Storage Table (OST) - is used for offline storage of items from a remote Exchange server
• Group Storage File (NST) - stores your Groups conversations and other local Groups data

The name "Personal Folder File" actually originally applied to the PST variety, but has been used as an "umbrella" name for all the varieties as well.

File identification

Files begin with hex bytes 21 42 44 4E.

Software

• libpff - library + tools to access PFF and OFF (Offline Folder File) formats
• libpst - includes utility to convert PST folders to both mbox and other formats

Links

• Wikipedia: Personal Storage Table
• PFF format specification (unofficial analysis) (archived)
• Personal Folder File (PFF) forensics (Analyzing the horrible reference file format) (archived)
• PST file format (official Microsoft description)
• PST file description
• Forensics Wiki page
• Digital Public Records - Outlook Calendars (Queensland government challenge)
• CodePlex PST SDK Archive
• Introduction to Outlook Data Files (.pst and .ost)