File Type Outlook Personal Information Store IconOutlook Personal Information Store
File Format Proprietary (Microsoft)
Usage Referenced by an application; not meant to be opened manually
Popularity ★ ★ ★ ★ ☆  Common

PST files store personal information used by Microsoft Outlook and Exchange. They contain a list of contacts and contact information, mail folders, and other user data.

Outlook Express users can import PST data using the program's Import feature. Entourage users can import data from PST files using Microsoft's PST Import Tool for Entourage.

IMPORTANT: PST files have a 2 GB limit. When a PST file gets close to the size limit, it may cause Outlook to noticeably slow down.

Info About Microsoft Outlook

Outlook is an e-mail client and personal information management program developed by Microsoft. In can be used to send and receive e-mail messages for multiple accounts. The program also includes a contact list, calendar, task manager, and journaling features. Outlook is included with some versions of Microsoft Office and is also available as a standalone application.

Open With

IconMicrosoft Outlook

IconMicrosoft Exchange Server

IconMicrosoft Outlook Express


IconMicrosoft PST Import Tool for Entourage

IconStellar PST to MBOX Converter for Mac

Published February 1, 2010
Information from the PC File Extensions Reference