Thank you Magic
It worked well.
For this sound problem, I didn't know what exaclty happen, but it seems some
packages have been uninstalled when I upgraded.
I thought to make before a back up of my favourite softwares with deselect.
https://en.wikipedia.org/wiki/Dselect
A very usefull software ! Also recommanded for cloning a system.
So, from the generated text file by Dselect before the problem, I could
restore the uninstalled packages and it was solved.
Greetings from France and hope everything's alright for you and your family
and friends.
