What a PST file is and why you have one

A PST file is Outlook's way of storing your email, calendar, contacts, and tasks in a single backup file on your computer. PST stands for "Personal Storage Table." You might have one because you exported your email before switching computers, your IT department gave you an archive of old messages, or Outlook created one automatically when you set up the program.

The file itself is just data — it won't open in a web browser or a word processor. You need Outlook (the desktop version, not Outlook.com in your browser) to read what's inside it. The process is straightforward once you know where to look.

Key Takeaways

  • PST files open only in Outlook on your computer, not in the web version or other email programs.
  • The fastest method is to drag the PST file directly into Outlook, which creates a folder for its contents.
  • If dragging does not work, use Outlook's File menu to open the PST as a data file instead of importing it.
  • Once open, the PST contents appear as a folder in your left sidebar alongside your regular email account.
  • You can search, read, and move messages from the PST, but changes you make do not sync back to the original file unless you export again.

The drag-and-drop method (fastest)

Open Outlook on your computer. Locate your PST file in Windows File Explorer or Mac Finder — it will have a .pst extension at the end of the filename. Click and hold the PST file, then drag it directly into the Outlook window. Outlook will recognize it and add its contents as a new folder in your left sidebar, usually labeled with the original account name or "Imported Folders."

This method works for most people and takes about 30 seconds. The PST folder then behaves like any other folder in Outlook — you can read messages, search within it, and move things around. If the drag-and-drop does not work on your computer, move to the next method.

Opening a PST file through Outlook's menu

If dragging does not work, open Outlook and go to File at the top left. Click Open & Export, then select Open Outlook Data File. A window will open asking you to find the PST file on your computer. Navigate to wherever you saved it, click it once to select it, then click Open.

Outlook will load the PST and add it to your folder list on the left side of the screen. The process takes a few seconds. You now have full access to everything that was stored in that file.

What you can and cannot do with an open PST

Once the PST is open in Outlook, you can read all the emails, view calendar events, see contacts, and search through everything inside it. You can also move messages from the PST into your regular email account by dragging them, or copy contacts from the PST into your main contact list.

What you cannot do: changes you make to messages in the PST (like marking them as read or moving them to a different folder within the PST) do not automatically save back to the original PST file. If you need to preserve changes, you must export the PST again after making edits. For most people, the PST is read-only — a way to look at old email without affecting your current account.

Troubleshooting: PST file won't open

If Outlook says the PST file is corrupted or refuses to open it, the file may have been damaged during transfer or storage. Try these steps in order: first, make sure you are using the desktop version of Outlook, not the web version. Second, restart Outlook completely and try again. Third, move the PST file to a different location on your computer (like your Desktop) and try opening it from there.

If none of that works, the PST file itself may need repair. Outlook includes a built-in repair tool called Scanpst.exe (on Windows) or the Inbox Repair Tool (on Mac). Search your computer for "Scanpst" or ask your IT department if you are using a work computer. Running this tool on the PST file before opening it often fixes corruption issues. If the file remains unopenable after repair, it may be too damaged to recover.

Keeping your PST file organized

Once you have the PST open, consider whether you want to keep it permanently in Outlook or just extract what you need. If you plan to use it regularly, leave it open — Outlook will remember it and reopen it each time you start the program. If you only needed to retrieve a few messages or contacts, copy what you need into your main account, then close the PST by right-clicking its folder and selecting Close Folder.

Store the original PST file in a safe location, such as an external hard drive or cloud storage, as a backup. Do not delete it from your computer unless you are certain you have extracted everything you need.

Frequently Asked Questions

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

No. PST files are specific to Outlook. Other email programs cannot read them directly. If you need to move email from a PST to Gmail or another service, you must first open the PST in Outlook, then export the messages in a format that other programs accept, such as CSV for contacts or EML for individual emails.

What if I don't have Outlook installed?

You need the desktop version of Outlook to open a PST file. Outlook.com in your web browser will not work. If you do not have Outlook, you can purchase Microsoft 365 (which includes Outlook) or use the free Outlook desktop app available from Microsoft. Some organizations provide Outlook as part of their email service.

Will opening a PST file delete the original?

No. Opening a PST file in Outlook does not delete or modify the original file on your computer. The PST remains where you saved it. If you make changes to messages within the open PST in Outlook, those changes stay in Outlook's memory but do not write back to the file unless you export it again.

Can I have multiple PST files open at the same time?

Yes. You can drag multiple PST files into Outlook or open them through the File menu one after another. Each PST will appear as its own folder in your left sidebar, and you can switch between them freely.