Like many people, Max Shafiq is looking 
on the Apple Discussion forums for a way to import Tiger Mail messages into Leopard Mail.
Another post in the same thread notes some of the ways not to do it:
I have the same problem Max. I’ve tried importing mailboxes (from the file menu), and also dragging the old Mail folders to the new Mac’s Library… both attempts only partially successful, with most mail missing completely.
Actually, the answer is fairly simple. Just follow the method in this previous Hawk Wings’ post on importing emlx messages into Tiger Mail. Nothing’s changed.
It involves quitting Mail, making a backup, creating a new Mailbox in your ~/Library/Mail/Mailboxes folder, copying in the individual emlx files (that is, the messages) you want to import, restarting Mail, selecting the new mailbox which will appear in the list of mailboxes “On my Mac” and rebuilding it. Voilà ! The messages appear, with timestamps and everything else nicely preserved.
Piece of cake.
Minor typo that I’ve spotted a couple of times this weekend -from Wikipedia:
“The viola (French, alto; German Bratsche) is a bowed string instrument.”
“Voilà ! (IPA: [vwala], approximately vwa-lah or wa-lah) is a French interjection roughly equivalent to “See!” or “There!”.”
Merde! Thanks. That’s shameful; I’ll fix it up right now.
I didn’t notice any trouble with my old Tiger mail appearing in Leopard Mail; and I just had my previous Mail folder in there.
Yea I’m a little confused here too. I upgraded the Mac Pro from Tiger to Leopard and all my mail, accounts and folders were upgraded right along with the OS. Upon first starting up Mail I was told a short conversion would be needed to transition the database to Leopard Mail, but that was it.
Are these people seeking solutions more along the lines of importing archived mailboxes into Leopard Mail? Perhaps something else?
Great tip! Thanks. For some people like me who did an erase and install of Leopard (it was time to clean up a little) and wanted to import all their backed up mails into mail. I experienced frustration trying the File-Import Mailbox and this worked perfect, thanks again!
@David — Yes, this is for importing archived mailbox or messages that somehow weren’t automatically imported at the time of upgrading.
I had a bit of wonkiness when restoring my backups after upgrading to Leopard [I use a ad-hoc method of restoring that takes a bit more time than the Migration Assistant, but reduces cruft because I manually bring over apps and their preferences] — I didn’t really have time to dicker around, so I just ran Migration Assistant, created a new account w/ my backed up mail and data, copied the mail from that new account to my real account, and then nuked the “new” user.
Hello,
My new mac died the other day and I am trying to import my mail from a backup to an old mac I have. How do I import my leopard mail into Tiger mail successfully.
Thanks in advance.
I suggest you guys take a look at this: http://discussions.apple.com/thread.jspa?threadID=1849306&tstart=0
A little bug in the Mail Migration from 10.4 to 10.5, great fix is given!