.PST Outlook Personal Storage Table
.pst

Outlook Personal Storage Table

A PST file is a Microsoft Outlook Personal Storage Table that stores copies of email messages, calendar events, contacts, tasks, and notes. It serves as the primary local data file for Outlook accounts configured with POP3 or as an archive.

File structure
Header schema
Records structured data
vnd.ms-outlook1997Proprietary
By FileDex
Not convertible

This format is not currently supported for conversion in FileDex.

Common questions

What is a PST file?

A PST file is a Microsoft Outlook Personal Storage Table that stores email, calendar, contacts, and other mailbox data locally on your computer.

How do I open a PST file without Outlook?

Use free tools like Kernel PST Viewer, SysTools PST Viewer, or the open-source readpst (libpst) utility to open and browse PST contents without Outlook.

How do I repair a corrupted PST file?

Run Microsoft ScanPST.exe (Inbox Repair Tool) included with Office. It is typically located in the Office installation folder under Program Files.

What makes .PST special

The PST format has gone through two major versions: the older ANSI format (Outlook 97-2002) with a 2 GB size limit and the Unicode format (Outlook 2003 and later) supporting files up to 50 GB by default. PST files use a node-based B-tree structure internally, with a header block, allocation maps, and a hierarchy of folder and message nodes. Microsoft has documented the PST format specification publicly, enabling third-party tools like Kernel PST Viewer, SysTools, and the open-source libpst to read and convert PST data. PST files are commonly used for email migration between Outlook installations, legal discovery (e-discovery), backup and archival of mailbox data, and offline access to email. Corruption in PST files can be repaired using the Microsoft ScanPST (Inbox Repair) tool included with Office installations.

Continue reading — full technical deep dive

Technical reference

MIME Type
application/vnd.ms-outlook
Developer
Microsoft
Year Introduced
1997
Open Standard
No