Can You Open a PST File in New Outlook? PST Support Status

Can you open a PST file in new Outlook?#

Yes, and the answer has changed twice in the last eighteen months, which is why so much of what you find online is wrong. As of July 2026, new Outlook for Windows can open a .pst file and let you read and search the mail inside it.

It cannot do that on its own. Microsoft's support page for opening Outlook Data Files states two requirements plainly: classic Outlook has to be installed on the same PC, and both clients have to be the same architecture, either 32-bit or 64-bit. Remove classic and the PST stops opening.

Microsoft's feature comparison between the two clients lists .PST as Partially available in new Outlook against Available in classic. That one word is carrying a lot of weight, so the rest of this article splits it into the three things people actually mean when they ask.

If your PST holds a decade of client mail, the line that matters is this one: do not uninstall classic Outlook, and do not delete the file, until you have opened it from the new client and seen your folders with your own eyes.

Open, import and export are three different questions#

Most of the disagreement online is two people confidently answering different questions. Separating them takes thirty seconds and makes the rest of this obvious.

• Open, sometimes called mounting, means the PST appears in your folder list and you browse it where it sits. Nothing is copied and the file stays on your disk.
• Import means the contents are copied into your mailbox. For a Microsoft 365 account that means the server, so the mail then syncs to every device and counts against your mailbox quota.
• Export means the reverse: writing mail out of a mailbox into a new .pst on disk, usually as a backup or a leaver's archive.

PST support by client, as of July 2026#

PST advice goes wrong the moment it forgets to name the client. Here is the full picture, labelled. Only one row does everything.

What Microsoft has actually shipped, and when#

PST support arrived in pieces rather than all at once, and every guide written at a different point in that sequence says something different. The release notes for new Outlook are the reliable record. These are the dated entries that matter.

One honest caveat, because it will affect what you see on your own machine. Several Microsoft Support articles still say importing a PST is not supported in new Outlook and send you to classic to do it, while the release notes say import shipped in March 2026 and was extended in June.

Both can be true at once. Features in new Outlook roll out gradually across accounts, and the support pages have not all caught up. The practical answer is to open Settings, Files and look for yourself rather than trusting any article, including this one. Check the date on anything you read about this, and check your own build.

How to open a PST file in new Outlook#

This is the read-only route. Use it when you want to browse an archive without moving anything, or when your mailbox does not have the room to absorb it.

1. 1

   Confirm classic Outlook is installed

   Both clients have to be on the same PC. If classic has already been removed, reinstall it before going further, because new Outlook on its own cannot read the file format.

2. 2

   Check that both are the same architecture

   They must both be 32-bit or both 64-bit. A mismatch is the single most common reason a PST refuses to open, and the error message rarely says so.

3. 3

   Copy the PST somewhere local first

   Work from a copy on the internal drive, not the original, and not a network share or a USB stick. Opening a PST across a network is unsupported and is a known way to corrupt one.

4. 4

   Open Settings, Files, Outlook Data Files

   In new Outlook, go to Settings and find the Files section. The panel has moved between builds, so if it is not there, search the settings pane for the word Outlook Data Files.

5. 5

   Select Add file and pick your PST

   Browse to the file and open it. If the PST has a password, have it ready. There is no recovery route for a forgotten PST password inside Outlook.

6. 6

   Verify what actually appeared

   The file shows up as its own tree in the folder list. Open three or four folders, including the oldest, and run a search you know should return a result. Do not stop at seeing the folder names.

7. 7

   Close it when you are finished

   Return to Settings, Files, Outlook Data Files, choose Manage on the file and select Close file. This removes it from the folder list. It does not delete anything.

How to import a PST into your mailbox#

Importing is the better long-term answer for an archive you still search. Once the mail is in a Microsoft 365 mailbox it syncs to your phone, it is covered by your organisation's backup and retention, and it stops being tied to one hard drive.

It is also the only route that makes the archive visible to anything other than Outlook, including any other client you might move to later.

1. 1

   Check your mailbox quota before you start

   A 20 GB PST needs 20 GB of room. Compare the PST's size on disk with your remaining mailbox space first. Running out mid-import is a slow problem to unpick.

2. 2

   Decide where it lands

   Import into a clearly named folder such as Archive 2014 to 2021 rather than merging it into your inbox. Separating it keeps your working folders usable and makes the import reversible by deleting one folder.

3. 3

   Try the import in new Outlook

   Go to Settings, Files, Import and follow the wizard. If that option is not present in your build, this feature has not reached your account yet. That is expected during a gradual rollout, not a fault.

4. 4

   Fall back to classic Outlook if needed

   In classic, use File, Open and Export, Import and Export, then Import from another program or file, then Outlook Data File. This is the route Microsoft still points to on several support pages, and it works today.

5. 5

   Import large archives in pieces

   Split a very large PST by year or by folder and import a chunk at a time. A failure then costs you one chunk instead of the whole run, and you can watch quota move between passes.

6. 6

   Let it finish syncing before you check

   The import writes locally, then uploads. Item counts look wrong until the sync completes, so give it time before deciding anything is missing.

7. 7

   Verify against the source, then keep the source anyway

   Compare folder item counts between the PST and the mailbox, spot-check the oldest year, and search for two or three specific old messages. Then keep the original PST on backup media for at least a few months.

Exporting to a PST from new Outlook#

This direction is in better shape than most people expect. New Outlook exports a whole mailbox or specific folders to a .pst from Settings, Files, Export, and it can run that export on a schedule, which classic never did on its own.

That makes it a reasonable backup for a personal account, and a reasonable way to hand someone an archive when they leave. Export writes a copy, so nothing disappears from the mailbox when you run it.

• Export one account at a time. The wizard works per account, not across all of them.
• Save the file somewhere local, then move it to backup media afterwards.
• A scheduled export is a backup, not an archive strategy. It still needs somewhere safe to live.
• Check the file opens before you rely on it. An export you have never opened is an assumption.

What to do when the PST will not open#

Most failures come down to one of five things, and only the last needs a repair tool. Work down the list in order.

If your archive lives in a client that cannot mount a PST#

Disclosure first: we build AI Emaily, so weigh this section accordingly.

Plainly: AI Emaily does not open PST files, and we are not going to imply otherwise. We connect accounts, not local files, over Gmail, Outlook and Microsoft 365, and IMAP. The Outlook setup walkthrough is at /docs/connect-outlook.

The consequence is easy to state. Mail that lives in your Microsoft 365 mailbox is reachable to us, including anything you have imported from a PST. A .pst sitting on your D: drive is not, and neither the AI features nor search can see inside it.

That is true of nearly every non-Microsoft client, which is why the order of operations matters more than the choice of client. Import the archive into the mailbox while classic Outlook is still installed and while you still have the file. Do that first, and your archive travels with you to any client you pick afterwards.

• Quota allows it and you still search the archive: import it into the mailbox. This is the option that ages best.
• The archive is huge or the quota is tight: keep classic Outlook installed purely as an archive reader, and use new Outlook for live mail.
• You rarely touch it: keep two copies of the PST on backup media and leave classic installed on one machine that can read them.
• Your organisation has compliance requirements: ask IT about online archive or import service options before doing anything yourself.

The short version#

New Outlook for Windows opens a PST read-only, and only alongside a matching classic Outlook install. Importing PST contents into the mailbox has been rolling out since March 2026 and was extended to calendar, contacts and tasks in June. Exporting to a PST works, including on a schedule. Classic Outlook remains the only client that does all of it without conditions.

The same web architecture that limits PST handling is what removed COM add-in support, so if both apply to you, they are one decision rather than two. In both cases the answer is often to keep classic installed for the specific job it still does best.

Whatever you choose, get the archive into the mailbox while you still have both the file and a working classic Outlook. That is the step that is painful to reverse, and it is the one people leave until the machine has already been wiped.