How to export an .olm file from Outlook for Mac
The archive is made from inside Outlook, on a Mac that still runs it. This is worth doing before a machine is handed back, a licence lapses, or an account is closed, once Outlook is gone, the mail is gone with it. It takes about a minute plus however long the export runs, and the result is a single .olm file you can copy anywhere.
What you get
One .olm file containing the items you ticked: mail, contacts, calendar, notes and tasks. Size roughly matches the mailbox, a few hundred megabytes is common, several gigabytes is not unusual.
Steps
- Open Outlook on the Mac. If it looks like the redesigned Outlook, find the New Outlook toggle at the top right of the window and switch it off. The export command lives in the legacy interface.
- On the Tools tab, click Export. If there is no Export button, look under the Outlook menu → File, and run Help → Check for Updates first.
- In the Export to Archive File (.olm) dialog, tick what you want: Mail, Calendar, Contacts, Tasks, Notes. Tick everything if this is a backup before a machine goes back.
- Click Continue.
- Choose where to save it, Downloads or Documents is fine, and click Save.
- Wait. A large mailbox takes several minutes and Outlook has to stay open. When the notification appears, click Finish.
- Copy the
.olmsomewhere durable: an external drive, or cloud storage. Then convert it here into something you can actually read.
What carries over
- Mail from the folders in the account, with attachments
- Contacts, calendar, tasks and notes, if you tick them
- The folder structure
- Both "On My Computer" folders and, for most accounts, the synced server folders that Outlook has downloaded
Good to know
- Export is missing or greyed out in the new Outlook for Mac. Microsoft's support pages still describe archive export as a legacy-Outlook feature, and a roadmap entry that listed OLM import and export for mid-2026 has not turned into a documented, shipped command. Toggling the new interface off is the working answer today.
- Support for legacy Outlook for Mac ends in October 2026. If the mail matters, make the archive now and convert it to a format that does not need Outlook at all.
- Outlook exports what it has locally. Mail that lives on the server and has never been downloaded, a large old mailbox that syncs only recent mail, is not in the archive. Scroll the old folders once so Outlook fetches them, or set the sync range to everything, before exporting.
- The export runs in Outlook's foreground. Leave the Mac alone while it runs and do not quit Outlook.
- Password-protecting the archive is not offered. An
.olmis not encrypted; treat it like any other copy of your mailbox.
Questions
Export is greyed out. What now?
You are in the new Outlook. Switch the New Outlook toggle off at the top right, let Outlook restart into the legacy interface, and Tools → Export is back. If the toggle is not there, your organisation may have pinned the new version; ask whoever administers it, or make the archive on another machine that still has legacy Outlook.
Where does Outlook put the .olm?
Wherever you told it in the Save dialog. Default is usually Downloads. It is a single file; Spotlight finds it with a search for .olm.
How big will it be?
Roughly the size of the mailbox, compressed a little because the archive is a ZIP container. Ten years of mail with attachments is commonly 2 to 10 GB.
Can I export just one folder?
The dialog exports by item type, not by folder. Export everything and pick the folders you want when you convert it here.
My Mac is gone and I never exported. Options?
If the account was Exchange or Microsoft 365, the mail is still on the server: add the account to any mail client and it comes back. If it was a local "On My Computer" mailbox and the Mac is wiped, the mail is gone. Time Machine backups of the Outlook profile are the only other place to look.