[MallyMal]

How does one transfer Mail contacts from one mac to another. These addresses auto-fill but are NOT saved in my address book so I'm not sure where Mail have these addresses saved.

[adamfishercox]

Go into address book, Go to File, Export, Address Book Library. Save it to your desktop, then move it to the other computer. On the other computer, open the Library.opml file that you moved over, and there's your contacts.

[MallyMal]

But these are contacts that are not in my Address Book. These contacts only show up in Mail but not in my Address Book app.

[adamfishercox]

I'm Pretty sure that any contact in Mail is also in Address Book. I don't know how it can be otherwise. There is no place for Mail to store names.

[Cold Warrior]

Not necessarily. The recently-used email addresses are stored separately. They should be in ~/Library/App Support/AddressBook/MailRecents-v4.abcdmr

At least that's what it looks like from what I can find. Opening it in Text Edit shows what look like my recent email addressees but not Address Book contacts.

You may be able to find some way to parse this text into a useful list, because it looks like garbage in Text Edit.

[pilotdude]

In Mail under the Window->Previous Recipients you should be able to see those Auto-Fill Addresses and you can add them to your Address Book from there. Unfortunately it doesn't let you specify a Group so you would have to go in to Address Book, look through your Library, put them in a Group and Export that Group. If there are a lot you could just Export your whole Library as a Group then if it doesn't Check for Duplicates on Import to your other computer you can do it through Card->Look for Duplicates.

Or if you don't care about the Auto-Fill info on your other computer you could Back Up the File Cold Warrior mentioned just in case then replace it with a copy of the one on the computer with the info you want. I haven't tried this method so hence the back up copy.

EDIT: I just tried out the second method in 10.5.2 and it worked fine. In this case on the computer you wanted to transfer info to, assuming you also have "Autofill" addresses on it you want to save, I would save those addresses to Address Book through Mail's Window->Previous Recipients menu, then quit Mail and remove the "MailRecents" file that Cold Warrior mentioned from Applications Support and replace it with a copy of the one with the info you want to transfer from the other computer. Then when you open Mail again all those addresses should be there. That seems like the least complicated method to me. You just might end up with a little extra clutter in your Address Book.

[MallyMal]

Very cool! Thanks everyone.