I could not boot in safe mode (nor with other modifier keys -single user -verbose mode and -target mode (but I could fix target mode with Startup panel)).
So I restored from time machine because it was more recent that my CCC backup.
All works then with Sharing Pane.
I kept my old status in a disk image if ever I need something I erased.
I made the combo installyou gave me just to be sure.
Thank you for the link to Pondini, I learnt a lot.
We can mark 'Solved".