Confused between PST and OST files? This guide explains the key differences, use cases, and how to convert between them.
PST Converter Tool
Export Outlook PST to 17 formats — PDF, MBOX, EML, Gmail, Office 365, IMAP — plus Contacts, Calendar, and Tasks. No Outlook needed. Runs on Windows 11 and Apple Silicon M4 Mac.
PST vs OST Files: Key Differences You Need to Know
What is a PST File?
PST (Personal Storage Table) is an Outlook data file used to store messages, contacts, and other items locally.
What is an OST File?
OST (Offline Storage Table) is a synchronized offline copy of your Exchange mailbox.
Key Differences
| Storage | Local PC | Local PC (synced from server) |
|---|
When to Use Which?
Use PST for archiving and backups. OST files are used automatically when you connect to Exchange or Office 365.
Michael Torres
Verified Technical Author 8+ Yrs ExperienceEmail Systems Expert
Specializes in Microsoft Exchange, Outlook PST/OST recovery algorithms, Office 365 tenant migrations, and enterprise cloud data integrity. All migration scripts and procedures are tested in isolated sandbox environments.
Recommended Tools for This Guide
PST Converter Tool
Export Outlook PST to 17 formats — PDF, MBOX, EML, Gmail, Office 365, IMAP — plus Contacts, Calendar, and Tasks. No Outlook needed. Runs on Windows 11 and Apple Silicon M4 Mac.