What does It Mean to Add a PST File to Outlook?
A PST file is an Outlook data file. Outlook for Windows reads the file straight from your disk.
You can attach the file in two ways. Opening shows the file as a separate set of folders. Importing copies the items into a mailbox you already use.
| Goal | Result | Method |
|---|---|---|
| Read old mail only | The PST stays separate | Method #1 |
| Read old mail from Account Settings | The PST stays separate | Method #2 |
| Merge old mail into a mailbox | Items are copied into your folders | Method #3 |
| Read mail in new Outlook | Mail opens as read only | Method #4 |
How do You Open a PST in Outlook?
Method #1: Open Outlook Data File (Free)
Who it suits. Users who want to read old mail now. Extra application. None.
- Start classic Outlook for Windows.
- Select File, then Open & Export.
- Select Open Outlook Data File.
- Choose the PST file and select Open.
The PST file shows at the bottom of the folder pane. Microsoft explains the steps on its page for opening and closing Outlook Data Files.
To remove the file, right click the data file and select Close. The PST file stays on your disk.
Can Account Settings Add a Data File?
Method #2: Account Settings (Free)
Use it when. You manage several data files in one list. Extra application. None.
- Select File, then Account Settings, then Account Settings again.
- Open the Data Files tab and select Add.
- Choose the file and select OK.
- Select Close to return to Outlook.
The Data Files tab lists the file path of every PST file. Use that list to find where Outlook stores a file.
How do You Merge a PST Into a Mailbox?
Method #3: Import and Export Wizard (Free)
Who it suits. Users who move old mail into a live mailbox. Extra application. None.
- Select File, then Open & Export, then Import/Export.
- Choose Import from another program or file and select Next.
- Choose Outlook Data File (.pst) and select Next.
- Browse to the PST file and set the duplicate rule. Choose between replacing duplicates, allowing duplicates and not importing duplicates.
- Select the folder to import and select Finish.
Import when you want the old mail inside your Exchange or Microsoft 365 mailbox. The mail then syncs to your other devices.
Choose Do not import duplicates when you import the same PST file twice.
Does New Outlook Read PST Files?
Method #4: New Outlook for Windows (Free)
Use it when. You switched to new Outlook and need old mail. Extra application. Classic Outlook.
- Start new Outlook and select Settings.
- Select Files, then Outlook Data Files.
- Select Add file and choose the PST file.
Microsoft lists the conditions on the same Outlook Data Files page. New Outlook needs classic Outlook on the same PC with the same 32 bit or 64 bit build. New Outlook needs a Microsoft 365 subscription too.
New Outlook reads Mail items only. Calendar, Contacts and Tasks inside the PST file remain out of reach. The ARM version of Outlook does not support the feature.
Can Outlook for Mac Import a PST File?
Outlook for Mac has no command to open a data file. The legacy client imports a PST file through File, Import and Outlook for Windows archive file (.pst).
Microsoft ends support for legacy Outlook for Mac in October 2026. Read the steps on the Microsoft page for importing a PST file into legacy Outlook for Mac.
Follow the guide to open a PST file on Mac for the Mac steps and the converter route.
What if Outlook Cannot Add the PST File?
- Copy the PST file to a local drive first. Add the copy and not your only copy.
- Read the guide for a PST file that cannot be opened when Outlook shows an error.
- Read the guide for disabled PST usage on a computer when a policy blocks the file.
- Use the guide to repair a corrupt PST file when the file is damaged.
- Use the guide for a PST file that cannot be found when the path is wrong.
Heads Up. An orphan PST file opens in Outlook only when the file is not damaged. A converter exports an orphan file without Outlook, as the PST migrator guide shows.
Where Else do You Go From Here?
- Read the guide to import PST files to Office 365 to move the file into Microsoft 365.
- Use the guide to restore Outlook data from a PST file when you need old mail.
- Mac users can follow the guide to export and import PST files in Outlook for Mac.
Frequently Asked Questions
How do You Add a PST to Outlook?
Select File, then Open & Export, then Open Outlook Data File. Choose the PST file and select Open. The file appears in the folder pane.
What is the Difference Between Opening and Importing a PST File?
Opening shows the PST as a separate data file. Importing copies the items into a mailbox you already use.
How do You Remove a PST File From Outlook?
Right click the data file in the folder pane and select Close. The PST file stays on your disk.
Can New Outlook Open a PST File?
Yes, with limits. New Outlook reads Mail items only and needs classic Outlook on the same PC.
Can Outlook for Mac Import a PST File?
The legacy client imports a PST file through File and Import. Microsoft ends support for it in October 2026.
Does a PST Import Create Duplicate Emails?
Only when you allow duplicates. The Import and Export wizard has a Do not import duplicates option.
Can You Read a PST File Without Outlook?
Yes. A converter reads an orphan PST file and exports it to EML, MSG, PDF or MBOX.
Author's Verdict
Use the open command to read old mail and the Import wizard to merge it into a mailbox.
Use classic Outlook for full folder access, because the new client reads mail only.
Key Takeaways
- Opening a PST file leaves the file as a separate data file.
- Importing copies the items into a mailbox.
- New Outlook shows Mail items only.
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