Talk about Google keyword overloading. Anyway, the problem at hand.
There’s a lot of information out there on how to convert Outlook to Apple Mail, with some Thunderbird along the way, but most are old enough to be out of date, but not old enough that people realise this.
The upshot is, just follow the steps documented at Migrate Mail Messages (Mac Thunderbird to Apple Mail version 4).
Now for the detail.
Apple’s Mail application used to store messages using the popular mbox format, which is pretty much the most widely used mailbox format, except for in Outlook, which uses Microsoft’s proprietary .pst format.
But around Mac OS X 10.4, Mail was changed to instead use the .elmx format. The different is namely that mbox files are pretty much an entire file full of the raw headers and text from every email in that mail folder; but .elmx uses parent mbox for each mail folder, but individual .emlx files for each message. Apparently in support of Spotlight, but I’m not sure.
This means that any import of mbox data may not work for OS X 10.4 and above.
On the Outlook side, .pst files are proprietary, and as far as I’m aware there are no non-Microsoft applications that can successfully parse these files. This will change, because Microsoft are currently working on documenting and open up the file format, as part of there open source promise. So the main (only?) way to export from Outlook is to write a program that asks Outlook directly for each email, and manually build mbox files. This is handled through the Windows MAPI interface, and requires Outlook to be running at the time so it can respond to the events being asked of it. Most programs that you buy for converting Outlook files, require you to have Outlook running at the time. They don’t really parse .pst files, they convert them by asking Outlook to hand over its message objects.
How to convert Outlook to Mail 4.0
Thankfully, Thunderbird provides its own MAPI import of Outlook files, so launch Outlook first, then download and run Thunderbird, and select import from the file menu. This should leave you with Thunderbird containing all of your Outlook mail.
Next you need to copy the Thunderbird mailbox files over to the Mac, because unsurprisingly enough, the Mac version of Thunderbird uses the same file format, a slightly modified mbox format. Just copy all the files in c:Users[username]Application DataThunderbirdProfiles over to the Mac and put it in /Users/[username]/Library/Thunderbird/Profiles/.
You could now run Thunderbird for Mac if you wanted, but you don’t need to if you’re importing into Apple’s Mail application.
Next step is to clean up the files so that Mail can correctly import them. If you import them as is, using Mail’s File/Import… function, you’ll end up with all the correct folders, but most of them will be empty. To clean them, you need to run the free Eudora Mailbox Cleanup. Don’t be fooled by the name, it also cleans Thunderbird files and imports them into Mail. You can download it from here: http://homepage.mac.com/aamann/files/EudoraMailboxCleaner.dmg.
It’s compiled for PowerPC only, so if you run it from Snow Leopard (OS X 10.6), then it will prompt you to install “Rosetta”, the PowerPC emulator for Intel Macs. Let Finder install Rosetta, and then copy the Eudora Mailbox Cleaner application from the .dmg image onto the desktop, as you need to run it from a read/write disk..
Eudora Mailbox Cleaner is a drop application, so you need to drag the parent directory that you copied from the Windows version of Thunderbird, and drop it into the Eudora Mailbox Cleaner application icon. You’ll get a prompt for the mailbox format, so select Mozilla/Thunderbird and click OK. It should then start converting all your mailbox data.
Once done, just run the Mail application and all your mailboxes will magically appear under your other mailboxes. If you click on them, most won’t have any messages, so select each folder in turn and select Mailbox/Rebuild from the Mail menu. Your messages should now appear correctly.
You’d think that Apple would have this all sorted by now.