The fastest way to open a PST file in Outlook

Open Outlook first, then use the File menu to import the PST file rather than trying to open it directly from your computer. In Outlook on Windows, go to File > Open & Export > Import/Export, choose "Import from another file", select PST file, and point to the file on your computer. On Mac, go to File > Import and select the PST file. Outlook will add the contents to your existing mailbox or create a new folder for them — you choose which during the import process.

The reason you import rather than open is that PST files are data containers, not applications. Outlook needs to read the file's contents and integrate them into its own system. Trying to double-click a PST file usually just opens Outlook without doing anything useful, which is why the import menu exists.

Key Takeaways

  • Use Outlook's Import/Export menu rather than trying to open the PST file directly from your computer.
  • Windows users go to File > Open & Export > Import/Export; Mac users go to File > Import.
  • During import, you can choose whether to merge the PST contents into an existing folder or create a new one.
  • If Outlook is not installed, you can view PST file contents using free tools like Kernel PST Viewer or Stellar PST Viewer, though these do not let you edit the messages.

Step-by-step import on Windows

Open Outlook and click the File tab in the top left. From the menu that appears, select Open & Export, then click Import/Export. A dialog box titled "Import and Export Wizard" will open.

In the wizard, highlight "Import from another file" and click Next. On the next screen, select "Outlook Data File (.pst)" from the list and click Next again. A file browser will open — navigate to wherever your PST file is stored on your computer, click it once to select it, and click Open. Outlook will ask whether to import into a new folder or merge with an existing one; choose whichever matches what you need, then click Finish. The import usually takes a few seconds to a few minutes depending on file size.

Step-by-step import on Mac

Open Outlook and click File in the menu bar at the top of the screen. From the dropdown, select Import. A dialog box will open asking what you want to import from.

Select "Outlook for Mac Archive File" or "Outlook Data File" depending on which format your PST is in (most are PST). Click the Continue button, then navigate to your PST file on your computer, select it, and click Import. Outlook will ask where to place the imported messages — you can create a new folder or add them to an existing one. Click Import again to finish.

What to do if you do not have Outlook installed

If Outlook is not on your computer, you have two options: install Outlook, or use a free PST viewer tool. Microsoft Outlook is part of Microsoft 365 (paid subscription) or can be purchased as a standalone application, though both require payment.

Free PST viewers let you read the messages, contacts, and calendar events inside a PST file without installing Outlook. Kernel PST Viewer and Stellar PST Viewer are both free and run on Windows; they show you what is in the file but do not let you edit or export individual messages. If you need to actually use the messages — reply to them, move them, or export them to another email service — you will need Outlook or a paid PST recovery tool.

Why you might have a PST file

PST files are Outlook's backup format. You might have one because someone sent it to you, because you exported your own Outlook mailbox as a backup, or because you are switching computers and want to move your old email. Some organizations also create PST files when employees leave, to archive their mailbox.

PST files can get large — a few years of email can easily be 500 MB to 2 GB — so importing a huge one into Outlook can slow things down temporarily while Outlook reads and indexes the contents. If your PST file is very large and your computer is slow, import it when you are not using Outlook for other work.

Fixing common import problems

If the import fails or Outlook says the PST file is corrupted, the file itself may be damaged. This sometimes happens if the file was not closed properly — for example, if Outlook crashed while the file was open, or if the file was copied while Outlook was using it. Try copying the PST file to a different location on your computer and importing from there, which sometimes resolves read errors.

If Outlook says "Cannot open your default email folders" or shows an error code, restart Outlook completely and try the import again. Close Outlook entirely (not just minimize it), wait a few seconds, then reopen it and repeat the import steps. If the error persists, the PST file may need repair; tools like Outlook Repair Tool (built into Windows) or third-party repair software can sometimes fix corrupted PST files, though this is less common than it used to be.

Frequently Asked Questions

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

Not directly. PST is Outlook's format, so other email services do not recognize it. You must import the PST into Outlook first, then export the messages from Outlook to a format the other service accepts — usually as individual EML files or as a CSV for contacts. Some third-party tools can convert PST to other formats, but Outlook is the most reliable path.

Will importing a PST file delete the original file?

No. Importing copies the contents into Outlook and leaves the original PST file untouched on your computer. You can delete the PST file after import if you no longer need it, but Outlook will not do that automatically.

What is the difference between importing and opening a PST file?

Opening a file usually means launching an application to view or edit it. PST files are not meant to be opened that way — they are data containers that Outlook reads. Importing tells Outlook to read the PST file and add its contents to your mailbox. This is the correct method for PST files.

Can I import a PST file into Outlook Web (Outlook.com)?

No. Outlook Web is the browser version of Outlook and does not have an import function for PST files. You must use the desktop version of Outlook (Windows or Mac) to import a PST. After importing into desktop Outlook, the messages will sync to Outlook Web if your account is set up to sync.

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

A small PST file (under 100 MB) usually imports in under a minute. Larger files can take several minutes to an hour depending on your computer's speed and how many messages are in the file. Outlook will show a progress bar during import. Do not close Outlook or shut down your computer while the import is running.