Mail Won't Import All Emails

Question

I just upgraded from an iMac G4 running 10.3.9 to a SR MacBook Pro with 10.4.9. I used the Migration Assistant to move my mail, but not all of the messages transferred. I also tried copying ~/Library/Mail manually but got the same results. When Mail imports the messages, the progress bar has the correct number (### of 2167), but it stops midway and I end up getting only 532 messages. Any suggestions?

Answer 1

The conversion from Mail 1.x to Mail 2.x is broken. Here’s an example of the most common variant of this problem and how to proceed in those cases:
Just upgraded, Most of my old Inbox is gone!
Your problem, however, is different in that you don’t even get an incomplete conversion. If Mail stalls during the conversion process, you may try to identify the mailboxes that Mail is choking on, quit Mail, move those mailboxes out of ~/Library/Mail/ (e.g. to the Destkop), and trash any Envelope Index-named files you may see in ~/Library/Mail/, so that Mail re-creates the index and tries to import the remaining mailboxes again, then manually import the problematic mailboxes as Other.
Alternatively, you may want to set up Mail from scratch and manually import your mail back afterwards. This would allow you to use Mail normally while solving the problem of importing the old mail as you see fit:
1. Quit Mail if it’s running.
2. In the Finder, go to ~/Library/. Move (not copy) the entire Mail folder out of there, to the Desktop.
3. In the Finder, go to ~/Library/Preferences/. Locate com.apple.mail.plist and move it to the Desktop.
4. Open Mail and set it up again from scratch. If given the option to import existing mailboxes or something like that, don’t. Just enter the account information and check that everything works fine.
5. You’ll have to re-configure all your settings in Mail > Preferences. For spam-related security reasons, the first thing you should do is go to Preferences > Viewing and disable Display remote images in HTML messages if it’s enabled.
6. Do File > Import Mailboxes and follow the instructions to import your mail from the old Mail folder that’s now on the Desktop. Import the Mailboxes folder first, then each of the POP-username@mailserver account folders, if any.
There are two ways to import Mail 1.x mailboxes into Mail 2.x. The obvious one is importing them as Mail for Mac OS X. But Mail 1.x stored mail in standard mbox format plus some additional support files, and this allows Mail 1.x mailboxes to also be imported as Other, i.e. as generic mailboxes in standard mbox format.
Importing as Mail for Mac OS X produces the best results when it works, because it takes into consideration all the files in the mailboxes, not just the mbox files where the messages are stored, and hence, allows information such as status flags to be preserved. Importing as Other, on the other hand, may work in cases where importing as Mail for Mac OS X doesn’t, because it looks at the mbox files only, ignoring the support files which is what Mail 2.x usually chokes on, but precisely because of that, information such as status flags is lost and previously deleted messages may reappear.
Hence, you may try importing as much as you can as Mail for Mac OS X, then import the problematic mailboxes as Other.
Note that what Mail asks for when importing depends on the format chosen. Mail always asks for the folder that contains the “things” to be imported. If Mail for Mac OS X is chosen as the data format, the “things” to be imported are the *.mbox folders, so you must choose the folder that contains them, not the *.mbox folders themselves. On the other hand, if Other is chosen as the data format, the “things” to be imported are the mbox files, so you must choose the *.mbox folders that contain them in that case.
Note also that some of the mailboxes now on the Desktop may have already been partially converted to the new *.emlx format during the previous (failed) attempt to convert them in place. If you tell Mail 2.x to import as Mail for Mac OS X a mailbox that already has a Messages folder, Mail will simply ignore the Mail 1.x files present there. If the mailbox was successfully converted to the new format, that’s fine, but if the conversion was incomplete, that’s not what you want.
As a result of doing all the above, some messages may be duplicated. Andreas Amann’s Mail Scripts has a Remove Duplicates script that you may find useful.
If all is well and you don’t miss anything, the files on the Desktop can be deleted, although you may want to keep them for a while, just in case.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder. You can easily locate any of the folders referred to in this post by copying the folder path here, doing Go > Go to Folder in the Finder, and pasting the folder path there.