Hi, I was hit by this as well. From googling around¹²³, it seems like it was caused by mariadb being updated and this somehow wasn't handled gracefully by akonadi/the update process. I never manually chose mariadb as the akonadi backend. Apparently the fix would've been to downgrade mariadb, upgrade the db, then upgrade mariadb. Removing the ~/.local/share/akonadi fixed it, but of course I lost the contents. Regards, Haakon ¹ https://forums.opensuse.org/showthread.php/548914-Cannot-get-Akonadi-to-star... ² https://bugs.archlinux.org/task/67668 ³ https://old.reddit.com/r/kde/comments/icz14s/ akonadi_wont_start_after_mariadb_update/g28tl43/?context=3