Manually Migrating Mail on OS X

If you need to manually migrate mail between for instance Tiger and Leopard you simply need to copy the preferences mail file and the mail folder itself.

The preferences file which holds information on your accounts, signatures, rules, etc. is located here:

 ~/Library/Preferences/com.apple.mail.plist

Transfer that to your new installation to the same folder.

Then rsync your mail folder (or transfer it in whatever way you like). Remember to close Mail on both Macs.

Make sure no Mail folder exists on the target machine below ~/Library and then rsync:

rsync -az ~/Library/Mail your_user_name@target_machine:~/Library

After that simply start Mail and it will ask for authentication details for your accounts.