After a few days of using El Capitan I decided to do a clean install today.
As always I backed up
~/Library/Mail and put it back after the clean install.
When I opened Mail after that, there were no accounts, no local mailboxes, no mail!
Since the I tried to restore every file that could be associated with Mail I could find from a TimeMachine backup:
~/Library/Mail ~/Library/Containers/com.apple.mail ~/Library/Preferences/com.apple.mail-shared.plist
Nothing has changed from that.
My Mails and Mailboxes are located in:
My Accounts are stored in the only file left in V2:
But Mail seems to ignore the whole
~/Library/Mail folder. Any ideas what I could do?