Import a PST file into Outlook

A PST file can come from an old computer, a former job, a backup or a conversion. Outlook can either open it, so it shows up as a separate set of folders, or import it, so its messages are copied into your current mailbox.

Open or import?

To read old mail, open it. To have it everywhere, including your phone, import it into a Microsoft 365 or Exchange mailbox.

Open a PST in classic Outlook

1. Choose File › Open & Export › Open Outlook Data File.
2. Select the PST and click Open.
3. It appears at the bottom of the folder pane. To close it, right-click its name and choose Close.

Import a PST in classic Outlook

1. Choose File › Open & Export › Import/Export.
2. Choose Import from another program or file, then Next.
3. Choose Outlook Data File (.pst), then Next.
4. Browse to the PST and choose a duplicate option:
   • Replace duplicates with items imported,
   • Allow duplicates to be created, or
   • Do not import duplicates, the safe choice when you might import the same file twice.
5. Select the folder to import (keep Include subfolders checked), choose Import items into the same folder in and pick your mailbox, then Finish.

Importing a large PST into a Microsoft 365 mailbox can take hours to upload. Keep Outlook open until it has finished.

The new Outlook

The new Outlook can open a PST under some conditions, but importing is still done in classic Outlook. Our guide to PST files in the new Outlook has the details.

Before you import

• Look inside first. The free PST Viewer shows the folders and messages in your browser without Outlook, so you can check it is the right file.
• Remove duplicates. If the PST was built from several backups, the same mail may be in it more than once. Remove duplicates counts them for free and writes a clean copy.
• Split a very large file. A PST of many gigabytes is slow to import and to search. Split it by year and import the years you need.
• Outlook says the file cannot be opened. Run the free health check, and see Outlook data file cannot be accessed.

Sources: Microsoft Support, Import email, contacts, and calendar from an Outlook .pst file; Open and find items in an Outlook Data File (.pst).

Frequently asked

Can I import a PST into Gmail? Not directly. See import a PST into Gmail.

Can I import an OST file? No. Outlook only opens an OST together with its account. Convert it with OST to PST first.

I imported the same file twice. Use Remove duplicates on an exported copy of the mailbox, or re-import with Do not import duplicates next time.