unusable-kmail

Не работает KMail?

First, you'll need to remove the various Akonadi configuration files, after stopping Akonadi.

They can be found in ~/.config and ~/.kde4/share/config and it's matching data from ~/.local/share/akonadi and ~/.kde4/share/apps

Then remove all *migratorrc files from ~/.kde4/share/config.

Next time you start Akonadi, it should initiate a migration.