The fastest way to open a PST file in Outlook

Open Outlook first, then use the File menu to import the PST file. In Outlook 2016, 2019, and Microsoft 365, go to File > Open & Export > Import/Export. Choose Import from another file, select Outlook Data File (.pst), browse to your PST file on your computer, and click Next. Outlook will then ask where you want the imported emails, folders, and contacts to land — you can merge them into an existing folder or create a new one.

If you're using Outlook on Mac, the process is slightly different: go to File > Import, select Outlook Data File, and navigate to your PST file. The import wizard will walk you through the same folder choices.

The import usually completes within a few minutes for files under 2 GB. Larger files may take longer, and Outlook may become unresponsive during the process — this is normal and does not mean something went wrong.

Key Takeaways

  • PST files are Outlook's native backup format, containing emails, calendar events, contacts, and folder structure from another Outlook account or installation.
  • The Import/Export wizard in Outlook's File menu is the standard way to open a PST file, and it merges the contents into your current mailbox rather than replacing it.
  • You need the PST file saved somewhere on your computer or an external drive — Outlook cannot open PST files directly from cloud storage like OneDrive or Google Drive.
  • If the PST file is corrupted or Outlook cannot read it, you may see an error message; repairing the file with the Inbox Repair Tool (scanpst.exe) sometimes fixes the problem.

Where to find your PST file before you import

PST files are usually stored in your user profile folder on your computer. On Windows, they typically live in C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook or C:\Users\[YourUsername]\Documents. On Mac, check Users/[YourUsername]/Documents/Microsoft User Data/Office 2011 Identities or Users/[YourUsername]/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles depending on your Outlook version.

If you don't know where your PST file is, use your computer's search function. On Windows, press Windows key + S, type *.pst, and search. On Mac, open Finder, press Command + F, and search for files ending in .pst. This will find all PST files on your computer.

PST files from other people or from an old computer are often stored on an external drive, USB stick, or in a Downloads folder. Check those locations if the standard folders don't contain what you're looking for.

What happens to your current Outlook data when you import a PST

Importing a PST file does not overwrite or delete your existing Outlook data. Instead, the contents of the PST file are added to your current mailbox. If the PST contains folders with the same names as folders you already have, Outlook will ask whether you want to merge them or create new folders with slightly different names (like "Inbox_1").

This means you can safely import multiple PST files without losing anything. However, if you import the same PST file twice by accident, you will end up with duplicate emails. If that happens, you can manually delete the duplicates or use Outlook's built-in duplicate-removal tools in some versions.

Repairing a PST file that won't open

If Outlook shows an error when you try to import a PST file — such as "Cannot open the Outlook Data File" or "The file cannot be accessed" — the PST file may be corrupted. Windows includes a built-in repair tool called the Inbox Repair Tool (scanpst.exe) that can sometimes fix these problems.

On Windows, the Inbox Repair Tool is usually located at C:\Program Files\Microsoft Office\root\Office16 (for Office 2016 and later) or C:\Program Files (x86)\Microsoft Office\Office16 on some systems. Search your computer for scanpst.exe to find it. Double-click the file, browse to your corrupted PST file, and click Start. The tool will scan the file and offer to repair it.

On Mac, there is no built-in repair tool. If a PST file is corrupted on Mac, you may need to use a third-party repair utility or contact the person who created the PST file to ask for a fresh copy.

Importing a PST file from an older version of Outlook

PST files created in older versions of Outlook (2003, 2007, 2010) work with newer versions of Outlook without conversion. The import process is the same regardless of which version created the PST file. However, some formatting or features specific to very old versions may not display correctly in newer Outlook.

If you're upgrading from Outlook 2003 or earlier, the PST file format is slightly different (called ANSI format). Newer versions of Outlook (2010 and later) use Unicode format. Outlook can read both, but if you plan to use the PST file in both old and new versions of Outlook, keep it in ANSI format — newer Outlook can read ANSI, but old Outlook cannot read Unicode.

Opening a PST file without importing it into Outlook

If you want to view the contents of a PST file without merging it into your current Outlook mailbox, you can open it as a separate data file. In Outlook, go to File > Open & Export > Open Outlook Data File, then browse to your PST file. The PST will appear as a separate folder in your Outlook sidebar, and you can read emails and contacts from it without changing your main mailbox.

This approach is useful if you're reviewing someone else's PST file, checking an old backup, or deciding what to import before you commit to merging it. You can close the data file at any time by right-clicking it in the sidebar and selecting Close.

Frequently Asked Questions

Can I open a PST file in Outlook on my phone?

No. Outlook on mobile devices (iOS and Android) does not support opening or importing PST files directly. You must import the PST file into Outlook on your computer first, then sync it to your phone through your email account.

What if the PST file is password-protected?

Outlook will prompt you for the password when you try to import or open the PST file. If you don't know the password, you cannot open the file — there is no way to bypass it. Contact the person who created the PST file and ask them for the password.

Can I open a PST file in Gmail or another email program?

PST files are specific to Outlook and cannot be opened directly in Gmail, Apple Mail, or other email programs. You must import the PST into Outlook first, then export the data in a format that other programs support, such as CSV for contacts or MBOX for emails.

How large can a PST file be?

Outlook 2010 and later support PST files up to 50 GB. Older versions of Outlook have smaller limits. Very large PST files may take a long time to import and can slow down Outlook while the import is running.

Will importing a PST file use up my email storage quota?

If you're using Outlook with an online account like Microsoft 365 or Outlook.com, importing a PST file will count toward your mailbox storage limit. If you're using Outlook with a local account (not synced to the cloud), the PST file takes up space on your computer but does not affect any online storage quota.