What a PST file is and why you might need to import one

A PST file is Outlook's native format for storing email messages, calendar events, contacts, and tasks on your computer. PST stands for "Personal Storage Table." When you export emails from Outlook or back up your mailbox, you get a PST file. If you've switched computers, recovered old emails, or received someone else's archived messages, you'll need to import that PST file back into Outlook so you can read and use those messages again.

The import process differs slightly depending on which version of Outlook you use — the desktop process (Outlook 2019, Outlook 2021, or Microsoft 365) works differently from Outlook on the web. This guide covers the desktop versions, which is where most people do this task.

Key Takeaways

  • PST files are Outlook's backup format and contain your emails, calendar, contacts, and tasks in a single file you can move between computers.
  • Desktop Outlook (not Outlook on the web) can import PST files directly using the File menu or by opening the file itself.
  • Before importing, check that your PST file is not corrupted by opening it in Outlook first — if it opens without errors, the import will likely succeed.
  • Imported emails will appear in a new folder or merge with existing folders depending on which import method you choose.
  • If your PST file is larger than 2 GB or shows signs of corruption, you may need to repair it with the Inbox Repair Tool (SCANPST.EXE) before importing.

Locating your PST file before you start

Before you can import, you need to know where your PST file is stored. If someone sent it to you, it's probably in your Downloads folder or in an email attachment. If you created it yourself by exporting from Outlook, check your Documents folder or wherever you chose to save it.

On Windows, PST files typically end with the .pst extension. On a Mac, Outlook stores data differently and does not use PST files in the same way — if you're on a Mac, you'll need to export to an OLM file instead and use a different import process.

Once you've found the file, note its full location (for example, C:\Users\YourName\Downloads\MyEmails.pst). You'll need this path when you import.

The simplest method: opening the PST file directly in Outlook

The fastest way to import a PST file is to open it directly. In Outlook, go to File > Open & Export > Open Outlook Data File. A dialog box will appear asking you to locate the file. Navigate to wherever your PST file is stored, select it, and click Open.

Outlook will then display the contents of that PST file in a new folder in your left sidebar, usually labeled with the file name. Your emails, calendar, and contacts from that file will appear there without affecting your current Outlook data. This method is safest because it doesn't merge anything — you can see exactly what's in the PST file before deciding what to keep.

If the file opens without errors, you know it's not corrupted. If Outlook shows an error message, the file may need repair before you can use it.

Importing PST data into your main Outlook folders

If you want to merge the PST file's contents into your existing Outlook folders (so emails go into your main Inbox, calendar events into your main Calendar, and so on), use the import function instead of just opening the file. Go to File > Open & Export > Import/Export. This opens the Import and Export Wizard.

Select Import from another file or program and click Next. Choose Outlook Data File (.pst) and click Next again. Navigate to your PST file, select it, and click Open. The wizard will then ask how you want to handle duplicates — you can replace duplicates, allow duplicates, or skip duplicates. Choose based on whether you think the PST file contains messages you've already imported before.

On the final screen, you'll see a folder tree showing where the imported data will go. By default, it imports into your main folders. You can change this by clicking on a different destination folder if you want everything to go into a subfolder instead. Click Finish to complete the import.

What to do if the PST file won't open or import

If Outlook shows an error when you try to open or import the PST file, the file may be corrupted. This is common with large PST files (over 2 GB) or files that were not closed properly when Outlook crashed. Windows includes a built-in repair tool called the Inbox Repair Tool, or SCANPST.EXE, that can often fix these problems.

To find and run SCANPST.EXE, search for "Inbox Repair Tool" in your Windows Start menu. When it opens, click Browse, navigate to your PST file, and select it. Click Start to scan for errors. If errors are found, the tool will ask whether you want to repair them — click Repair. The tool creates a backup of the original file (with a .bak extension) before making changes, so you won't lose the original if something goes wrong.

After repair completes, try opening or importing the PST file again. If it still fails, the file may be too damaged to recover, and you may need to contact the person who created it to ask for a fresh copy.

Imported emails appearing in the wrong place or not at all

Sometimes imported emails appear in unexpected folders or seem to disappear. This usually happens because Outlook created a new folder structure instead of merging with your existing folders. Check your folder list on the left side of Outlook — you may see a new folder with the PST file's name containing all the imported data.

If you want to move emails from that folder into your main Inbox, you can drag and drop them. Select the emails you want to move, drag them to your main Inbox folder, and release. Outlook will ask whether you want to move or copy them — choose Move if you want them out of the imported folder, or Copy if you want to keep a backup in both places.

If emails don't appear at all after import, check whether Outlook is filtering them. Some emails may have been marked as spam or sorted into a subfolder based on rules you've set up. Use the search function (Ctrl+F on Windows) to search for a sender's name or a keyword from an email you know should be there.

Preventing PST file problems in the future

PST files can become corrupted if Outlook closes unexpectedly or if the file gets too large. To avoid problems, keep your PST files under 2 GB by archiving old emails regularly. In Outlook, go to File > Cleanup Tools > Archive to move old messages to a separate PST file automatically.

If you're backing up your mailbox, use Outlook's built-in export function rather than copying PST files manually. And if you're receiving a PST file from someone else, ask them to verify it opens without errors on their computer before sending it to you. This straightforward check catches corruption problems before they become your problem.

Frequently Asked Questions

Can I import a PST file into Outlook on the web?

No. Outlook on the web (the browser version) does not support PST file imports. You must use the desktop version of Outlook (installed on Windows or Mac). If you only have access to Outlook on the web, you'll need to install the desktop version first, import the PST file there, and then sync it to your online account.

What's the difference between opening a PST file and importing it?

Opening a PST file displays its contents in a separate folder without changing your main Outlook data. Importing merges the PST file's contents into your existing folders. Use open if you want to review the file first; use import if you want the data integrated into your main mailbox.

How long does it take to import a large PST file?

A PST file under 500 MB usually imports in a few minutes. Larger files can take 10 to 30 minutes or longer depending on your computer's speed and how many items are in the file. Don't close Outlook while the import is running, or you may have to start over.

Will importing a PST file create duplicate emails?

It can, if those emails already exist in your Outlook mailbox. The import wizard lets you choose how to handle duplicates — you can skip them, allow them, or replace the existing versions. Choose "skip duplicates" if you think the PST file contains emails you've already imported.

What if the PST file is password-protected?

Outlook will prompt you to enter the password when you try to open or import the file. If you don't know the password, you cannot access the file. Ask whoever created or sent you the PST file for the password.