Avira ainstall stuck windows "Installing..." asks for reboot, the, restarts install, then asks for reboot...

Hello,

I am stuck in an install loop. I install avira, the windows appears in bottom-right 'Installation en cours" 4 or 5 min

Then a window appears Redémarrez votre appereil " reboot your machine".

I rebot, then the install starts again, then ask to reboot, the satrs again..

It's weird because avira seems installed. Ther is the icon on my desktop.

How can I do to end the install ?

cheers