> A yes/no dialog appeared during the upgrade with a message
> that it wanted to convert something. But I thougt it is a minor change
> and I did not want it, so I pressed no.
What did that dialog exactly say? It is very relevant what is said and what was your reponse to it was. Such a dialog is not visible in the automatic Apport logs.
What if you try 'sudo apt-get remove "mariadb-*"' and then reinstall?
> A yes/no dialog appeared during the upgrade with a message
> that it wanted to convert something. But I thougt it is a minor change
> and I did not want it, so I pressed no.
What did that dialog exactly say? It is very relevant what is said and what was your reponse to it was. Such a dialog is not visible in the automatic Apport logs.
What if you try 'sudo apt-get remove "mariadb-*"' and then reinstall?