How to Create an Outlook PST File: A Complete Guide
A PST file (Personal Storage Table) is Microsoft Outlook's local file format for storing emails, contacts, calendar items, tasks, and notes directly on your computer. Knowing how to create one gives you control over your data — whether you're archiving old emails, backing up your mailbox, or migrating to a new machine.
What Is a PST File and Why Create One?
Unlike emails stored on a mail server (via IMAP or Exchange), a PST file lives on your local drive. This makes it useful for:
- Archiving — moving older emails off your active mailbox to reduce size
- Backup — keeping a local copy of important correspondence
- Migration — transferring your mailbox to a new PC or Outlook installation
- Offline access — reading archived mail without an internet connection
PST files are distinct from OST files (Offline Storage Tables), which are cached copies of server-based mailboxes (like Microsoft 365 or Exchange accounts) and aren't meant for manual archiving.
How to Create a New PST File in Outlook
The steps vary slightly depending on your Outlook version, but the core process is consistent across Outlook 2013, 2016, 2019, and Microsoft 365 desktop.
Method 1: Create a PST from Account Settings
- Open Outlook and go to File → Account Settings → Account Settings
- Click the Data Files tab
- Select Add
- Choose Outlook Data File (.pst) from the dialog box
- Name the file and choose a save location on your drive
- Click OK
The new PST file will appear in your Outlook folder pane as a separate data store. You can drag emails, contacts, or calendar items into it manually.
Method 2: Use the Archive Feature to Auto-Generate a PST
Outlook's built-in AutoArchive tool creates a PST automatically based on rules you define:
- Go to File → Options → Advanced
- Click AutoArchive Settings
- Set your archive frequency, age threshold (e.g., items older than 6 months), and destination path
- Click OK
Outlook will generate an archive.pst file at the specified location and move qualifying items into it on schedule.
Method 3: Manually Export to a PST File 📁
This method is best for one-time backups or migrations:
- Go to File → Open & Export → Import/Export
- Select Export to a file, then click Next
- Choose Outlook Data File (.pst)
- Select the folders you want to export (check Include subfolders if needed)
- Set a destination file path and choose how to handle duplicates
- Click Finish
You can optionally password-protect the PST at this step — useful if the file will be stored externally or shared.
Key Variables That Affect How This Works
Not every Outlook setup behaves identically. Several factors shape your experience:
| Variable | How It Matters |
|---|---|
| Account type | POP3 accounts already store mail locally in a PST by default; IMAP and Exchange accounts use server storage and OST files |
| Outlook version | Older versions (pre-2013) use a different PST format with a 2GB file size limit; newer versions support files up to 50GB |
| Microsoft 365 plan | Some enterprise plans restrict local data export through IT policy |
| Operating system | PST files are Windows-only; Outlook for Mac uses .olm files instead |
| File location | Storing a PST on a network drive or cloud-synced folder (like OneDrive) can cause corruption — local drives are strongly recommended |
PST File Size and Format: What You Should Know
Outlook uses two PST formats:
- ANSI format — used by Outlook 2002 and earlier; hard 2GB cap
- Unicode format — used by Outlook 2003 and later; supports up to 50GB per file
If you're on a modern Outlook version, you'll always create Unicode PST files by default. Still, very large PST files (above 10–15GB) can slow Outlook down noticeably and become harder to manage or repair if they're ever corrupted.
Best practice: split archives by year or project rather than letting a single PST grow indefinitely.
Managing and Accessing PST Files
Once created, a PST file can be:
- Opened in Outlook via File → Open & Export → Open Outlook Data File
- Copied or moved like any regular file when Outlook is closed
- Repaired using Microsoft's built-in ScanPST.exe (Inbox Repair Tool) if corruption occurs
- Password-protected — though Outlook's native PST password is relatively weak and not a substitute for full-disk encryption
📌 Always keep a backup copy of your PST in a separate location. A single corrupted file with no backup means permanent data loss.
Where PST Fits Into Different Outlook Setups
The relevance of PST files shifts considerably depending on how you use Outlook:
- Home users on POP3 — PST files are the default storage mechanism; archiving and backup are straightforward
- Corporate Exchange or Microsoft 365 users — email lives server-side; PST is mainly used for local archiving or export, and IT policies may limit what's exportable
- Users migrating between PCs — PST export is the most reliable method for moving Outlook data manually
- Mac users — PST isn't natively supported; the Outlook for Mac ecosystem operates differently
How useful PST creation is — and which method makes the most sense — depends heavily on your account type, what you're trying to accomplish, and whether your environment places any restrictions on local data storage. Those specifics are the part only your own setup can answer. 🗂️