My Thunderbird email accounts disappeared, including all emails and all contacts (Thunderbird opens up completely blank, in other words). My profile is still intact, and as far as I can tell the prefs.js file is not corrupted (it opens with a text editor). But I cannot open Thunderbird preferences, account settings, etc. at all. I have tried updating and reinstalling, but no luck. Creating a new profile and moving the old to the new results in the same problems, and downgrading apparently means I can no longer use the profile that I have. I am using Thunderbird on Manjaro OS with KDE. I am not sure exactly when this problem started, but I first noticed it a few days back I think a rather large system update.