After a hard desktop crash (computer got too warm), on reboot Akonadi doesn't work anymore. Kmail reports "The Email program encountered a fatal error and will terminate now. The error was: Could not create collection trash, resourceId 3" See also https://discuss.kde.org/t/kmail-fatal-error/18393/22. akonadi ctl fsck and vacuum don't end. Curiously enough, akonadi can run and sort my mail using the configured filters into the right folders.