Resolved Transferring mail with clean install?

[splitpea]

Mail on the old computer was... imperfectly stable, a bit corrupt, and a mess in terms of accounts (with more than a dozen defunct disabled accounts). So I want to import all my "On My Mac" mail archives without the accounts and preferences. And I want to get recent mail in without creating too many duplicates.

I've already set up the new accounts cleanly on the new Mac. The new POP3 accounts have downloaded all their mail, and I've deleted the stuff that would be duplicates. And I've got a copy of the contents of the old computer's ~/Library/Mail/V5 ready to import.

Here's the problem: Those contents consist of folders with UUIDs as their names (example: "884F8CF2-42BF-4325-8938-5F48563FCA06"). When I import them, Mail includes those UUIDs as parent folder names for the actual mailbox folders.

Worse: I have literally hundreds of deeply nested mail folders. For each level of nesting, the import creates 4 empty parent folders in between the actual parent and the actual child. Cleaning this up after import would take hours. Maybe days.

Is there a way to do this that doesn't completely and utterly suck?

 

[splitpea]

Answered my own question again. You CAN export nested folders from Mail. In the sidebar, you have to expand all the subfolders to the full depth, then click the parent folder and shift-click the last sub-folder in the list.

Then you can use the "Apple Mail" option on import and they import perfectly.

Inboxes and sent/junk/trash will export with numbers instead of account names, which is a little annoying. But you can export/re-import those too (tho they won't actually re-import as inboxes/sent/etc, just as normal local folders).

Hope this helps someone else in the future!