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. Apple Mail cannot open a PST file, so importing PST to Apple Mail is really a two step job. First convert the PST to MBOX, using free Thunderbird as a bridge or the free readpst tool on a Mac, then import that MBOX into Apple Mail through File, Import Mailboxes. A converter does the first step in bulk.
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Why Apple Mail will not take a PST?
The reason this feels harder than it should is simple. PST is Microsoft Outlook’s Windows format, and Apple Mail has no idea how to read it. What Apple Mail does understand is MBOX. So there is no direct road from a PST into Apple Mail, and any guide that promises one is quietly doing a conversion in the middle.
Once you see it that way the job is clear. You convert the PST to MBOX first, then import that MBOX into Apple Mail. Everything below is just different ways to make that MBOX, two of them completely free. One quick note on scope, Apple Mail holds mail, so a PST’s calendars and contacts do not land here, those go into Apple Calendar and Contacts separately.
No direct road. MBOX is the bridge from a PST into Apple Mail.
“The whole task hinges on one fact, Apple Mail reads MBOX and not PST, so you are really doing a PST to MBOX conversion and then a plain import. You do not need to buy anything for it. Thunderbird will happily swallow a PST and hand you MBOX files, and on a Mac readpst does the same from the command line. The one thing I always check afterwards is the folder hierarchy, a good conversion keeps your Inbox, Sent and subfolders intact rather than dumping everything into one pile.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
The free bridge, Thunderbird to MBOX
The most dependable free route uses Thunderbird, which is free and runs on both Windows and Mac. It reads the PST and gives you MBOX files.
Get the PST into Thunderbird. Install Thunderbird and the free ImportExportTools NG add-on. On Windows, Thunderbird can also import your Outlook mail directly. Our guide to import a PST to Thunderbird walks through this in full.
Export the folders as MBOX. Right click a folder, choose ImportExportTools NG, then Export folder, and save it as an MBOX file. Repeat for each folder you want, or export a whole account at once.
Move those MBOX files to your Mac if you made them on Windows, and you are ready for the import step further down.
On a Mac, the readpst way
If you are already on the Mac and comfortable with a single command, you can skip Thunderbird entirely. The free libpst package includes readpst, which converts a PST to MBOX right on macOS.
Install libpst, then run readpst -o outputfolder yourfile.pst. It writes out MBOX files that mirror your PST folders, ready to import into Apple Mail. It is the quickest free path for a Mac user who does not want to install a mail client just to do a conversion.
Pick the bridge that suits you. Both cost nothing.
Import the MBOX into Apple Mail
However you made the MBOX, the last step is the same and it is easy.
Open Apple Mail, choose File, then Import Mailboxes, select Files in mbox format, and point it at your MBOX files. Apple Mail brings them in under an Import folder in On My Mac, keeping your messages and their attachments. Drag them wherever you like from there, and the migration is done.
The bulk way, a PST converter
The free routes are ideal for a PST or two. When you have many PST files, very large ones, or a damaged or orphaned PST that Thunderbird chokes on, a dedicated converter handles the first step cleanly. The PCDOTS PST Converter loads PST files, including inaccessible ones, and exports them to MBOX in bulk while keeping the folder hierarchy intact, so you then import the result into Apple Mail the same way. Being straight about it, the tool runs on Windows, so you make the MBOX there and move it to the Mac, whereas readpst does the conversion on the Mac itself for free. Its real value is scale and difficult PST files, not a different result. A free version converts the first ten items per folder so you can test it.
The tool route, for many or damaged PST files.
Here are the steps with the screens.
Step 1. Install and run the converter on Windows, then open the menu.
Step 2. Choose Email Data Files, Outlook PST, and add your files.
Step 3. With the files loaded, open the Export menu and choose MBOX, then a destination.
Step 4. Save, then open the output folder and move the MBOX to your Mac to import.
For more on the two halves of this trip, see our guides to convert PST files to MBOX and to import MBOX to Apple Mail.
The methods compared
Match the route to where you are working and how many PST files you have.
| Method | Best for | Good to know |
|---|---|---|
| Thunderbird bridge | One or a few PSTs, free | Cross platform, needs the add-on |
| readpst on a Mac | Mac users, free | One command, no mail client |
| PST Converter tool | Many or damaged PST files | Windows, bulk, keeps folders |
Frequently asked questions
Can Apple Mail open a PST file directly?
No. PST is Outlook’s Windows format and Apple Mail cannot read it. You convert the PST to MBOX first, then import the MBOX into Apple Mail.
How do I import PST to Apple Mail for free?
Use Thunderbird to import the PST and export the folders as MBOX, or on a Mac run readpst to make the MBOX, then in Apple Mail choose File, Import Mailboxes, Files in mbox format.
Do I need Outlook for Mac to do this?
No. Some guides route through Outlook for Mac, which is a paid app. The free Thunderbird and readpst routes both make the MBOX without it.
Will my folders and attachments be kept?
Yes. A good conversion preserves the folder hierarchy, and the MBOX import brings your messages with their attachments. It is worth checking the folders arrived intact afterwards.
What about my calendar and contacts in the PST?
Apple Mail holds mail only. Calendars and contacts from a PST do not go into Apple Mail, they would be moved into Apple Calendar and Contacts separately.
Can I convert many PST files at once?
Yes. A converter can process a batch of PST files to MBOX in one pass and keep each one’s folders, which is easier than doing them individually.
It is a two step trip, not a wall
If the direct route looked blocked, that is because it is, but the detour is short and mostly free. Convert the PST to MBOX with Thunderbird or, on a Mac, with readpst, then let Apple Mail import the MBOX, and your Outlook mail settles in with its folders and attachments intact. Keep a converter in reserve for when the PSTs are many or damaged. Either way, once you know the bridge is MBOX, moving your mail from Outlook to Apple Mail turns out to be far less daunting than it first appears.
