Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. IMAP is a live account protocol, not a file, so nothing opens an OLM straight into it. To import OLM to IMAP you move the mail through a client, get the OLM into Thunderbird, add the IMAP account, and drag the messages so they upload to the server, or use a tool that reads the .olm and uploads to the account directly.
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What OLM to IMAP really means?
Clear this up first and the rest makes sense. An OLM is a closed file that Outlook for Mac writes, and IMAP is not a file at all, it is the protocol for a live mail account whose mail lives on a server. Gmail, iCloud, Office 365 and Yahoo are IMAP hosts, not files you can point at. So importing OLM to IMAP means lifting the mail out of that file and uploading it into a server mailbox, where it then syncs to every device. Nothing reads an .olm straight up to a server, so this is always a two-step move, get the mail into something that speaks IMAP, then let it upload.
IMAP is a server mailbox, so the mail is uploaded through a client, then it syncs everywhere.
“People picture IMAP as a place to drop a file, but it is a live account, so the mail has to be uploaded to the server by something that can log in. That is the part to plan around. If the old account is still alive, you may not need the OLM at all. If it is a true archive, you get the mail into Thunderbird first and drag it up, or let a tool log in and upload directly. And do check whether the host wants an app-specific password, Gmail and iCloud will refuse the normal one when two-factor is on, and that trips up more migrations than anything else.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
First, is the account still live
Before converting anything, check one thing that can save the whole job. Plenty of OLM files are just an archive of an account that is still running. If that account still works, its mail already sits on the server, so adding it to any mail app pulls it down, and moving it to a different IMAP account is a simple drag between the two. The OLM only becomes the thing you must deal with when the account behind it is gone, or the mail lived only on the Mac. So confirm that first, because a live account turns this into a two-minute task with no conversion at all.
The free way, through a client
When you do have a standalone OLM, the free path runs through a mail client, usually Thunderbird. There is a catch worth naming, Thunderbird cannot read OLM, so you first convert the .olm to MBOX or EML, the formats it understands, and import that. Once the mail is sitting in Thunderbird, add your IMAP account to Thunderbird, then drag the messages into the account’s folders. That drag is the actual upload, Thunderbird pushes each message to the server, and from there it syncs to your other devices. The upload is free, the only real hurdle is that first conversion, since OLM has no built-in free reader.
Dragging the mail onto the IMAP account is what uploads it to the server.
The app password most hosts want
This one detail derails more OLM to IMAP moves than anything else, so it is worth its own note. If your IMAP account has two-factor turned on, and most now do, the host will not accept your normal password from a third-party client or tool. You generate a separate app-specific password in the account’s security settings and use that instead. Gmail, iCloud, Yahoo and AOL all work this way. The server addresses are ordinary too, imap.gmail.com, imap.mail.me.com for iCloud, and outlook.office365.com for Microsoft 365. Sort the app password out first and both routes below go smoothly.
The direct way, in one step
If you would rather skip the client juggling, a converter does both hops at once. The PCDOTS OLM Converter reads the .olm and uploads straight to your IMAP account, you point it at the file, pick IMAP, enter the host, your address and the app password, and it pushes the mail up to the server itself. No converting to MBOX first, no dragging. It runs on Windows, so copy the .olm over from the Mac, and a free version handles the first ten items so you can confirm it connects before you buy. This is the tidy route for a standalone OLM going to any IMAP host.
The tool route, an .olm read and uploaded straight to the IMAP account.
Here are the tool steps with the screens.
Step 1. Install and run the software on Windows, then open the menu.
Step 2. Choose Outlook for Mac OLM files and add your .olm.
Step 3. Open Export and choose IMAP.
Step 4. Enter the host, your address and app password, then upload.
For the first hop on its own see import OLM to Thunderbird. For specific hosts, we have guides to OLM to Office 365 and OLM to a Gmail account, both of which are IMAP under the hood.
The methods compared
Match the route to where your mail is and how hands-on you want to be.
| Situation | What to do | Good to know |
|---|---|---|
| Account still live | Add it, drag between accounts | No conversion needed |
| Standalone OLM, free | Into Thunderbird, drag up | Convert OLM first, app password |
| Standalone OLM, direct | A converter, upload to IMAP | Windows, one step |
Frequently asked questions
Can I import an OLM straight into IMAP?
No. IMAP is a live account, not a file, and nothing reads an OLM directly to a server. The mail has to be uploaded through a client or a tool.
What counts as an IMAP account?
Any mailbox reached by the IMAP protocol, including Gmail, iCloud, Office 365, Yahoo and most business email. The mail lives on the host’s server and syncs to your devices.
Why will not my normal password connect?
If two-factor is on, hosts like Gmail and iCloud block the normal password for third-party access. Generate an app-specific password in the account settings and use that.
Is there a free way to do it?
Yes, if you get the OLM into Thunderbird first, then drag the mail onto the IMAP account to upload it. The catch is the OLM has to be converted to MBOX or EML before Thunderbird can read it.
Do I need Outlook for Mac?
Not for the tool route, which reads the .olm on Windows. You would only need Outlook for Mac if you were re-importing the OLM there to drag it out by hand.
Will folders and attachments carry over?
Yes. A proper move keeps the folder layout and the attachments inside each message as it uploads to the IMAP account.
Which path fits you
So it really comes down to your starting point. If the old account still works, skip the file, add it somewhere and drag the mail across, done. If you have a standalone OLM and do not mind a couple of steps, get it into Thunderbird and drag it up to your IMAP account for free, just sort the app password out first. And if you would rather it happen in one pass, a converter that logs in and uploads straight to the server is the cleaner choice. Pick by where your mail sits today, and the migration follows from there.
