I had this problem last 2 days, problem solved for me by dowgrading my
version of windows 10, the last auto updates is the one that make it
happen !the screen of my headset is light on now,
Same problem here since Yesterday, my rift doesn't start, black screen
and the notification on my main monitor is : "Hardware notification :
your guardian system is not working"Error 406 on steam, black
screen.(All my sensors are ok, touchs are fine ...