I upgraded Thunderbird from 9 to 10 and now folders are missing.
In my Local Folders I had a folder named "Backup2". It no longer shows in Thunderbird.
But when I go to
%APPDATA%\Thunderbird\Profiles\default\Mail\Local Folders I can see
Backup2.sbd folder with all the subfolders inside. How to get Thunderbird to show it in the UI?
Other folders such as
Backup3 are still working OK.