Max,
I'm having trouble after updating from beta 5 to GM with all of my "On my Mac" (archived) folders and their emails disappearing. (I had this same issue going from beta 5 to beta 6 and had to return to v1 and update to v5 beta to keep my "On my Mac" folders.) I have no problems with Gmail or other mail folders in the InBox or even in the Sent box; those emails seem stable. The problems seems to be restricted to the "On my Mac" folders.
When I follow your instructions from another thread, while running under beta 5 (that is, moving com.apple.mail to desktop) and then re-start Mail, all the folders inside "On my Mac" also disappear, just like when I updated to GM. When I move the folder back into the Container folder, and re-start Mail, the folders and their emails are present again.
How can I stabilize this thing and move onto GM without losing my "On my Mac" folders?
Thanks.