Sorry for the french, some of you undersood it. It will probably be less precise in english ...
I disabled Cortana. Now I don't have the error message, the souncard of the controler is not used anymore by another process. So the problem shoud be solved ...
However, the problem is still the same :
- with cue disactivated, the main sound (= master ?) is in the speakers (normal) AND the headphones (not normal)
- with cue activated, the sound in the headphones is louder (logical) and the sound in the speakers stay the same (normal).
The headphones are so impossible to use correctly. The cue seems to work, but not the master. However, I didn't change the audio option :
