1. Mail stores your mail messages and attachments in ~/Library/Mail.
Inside that folder there is a bunch of stuff going on… Most notably, there
will be a folder for each email account, as well as a folder called
‘Mailboxes’. ~/Library/Mail/Mailboxes is the root folder for all the local
generic boxes on the computer. That is, depending on your specific folder
behaviors (where you store Junk, Sent, etc) you will see a corresponding
folder here.
Anyway… Explore in this folder and compare it to the folders you see in
Mail.app and you’ll begin to understand the relationship.
2. Your actual account settings reside in
~/Library/Preferences/com.apple.mail.plist
So, the steps I used to manually migrate Mail.app from old > new computer
are as follows.
1. boot old computer into Target Disk Mode, connect to the new computer.
2. replace ~/Library/Mail on the new computer with the corresponding folder
from the old computer.
3. replace ~/Library/Preferences/com.apple.mail.plist on the new computer
with the corresponding file from the old computer.
Now, if you launch Mail.app on the new machine, it will do one of 2 things.
1. if the Mail.app versions are the same, it will chug for a minute and then
display everything identically to the old computer.
2. If the Mail.app versions are not the same (ie 10.3 to 10.4) it will
‘import’ the messages. What this is actually doing is upgrading the format
of the messages in the folder structure that you just moved. It takes a few
minutes, but when its done, you should see a nicely migrated mail client.
Finally, press ‘get mail’ and you will be prompted for the password for the
email accounts that you migrated. The passwords were not moved because you
didn’t move the keychain items for them. It’s easiest to just type them in,
rather than move the keychain.