i think there was a tread around about steamvr going into safe mode and refusing to see the headset until a manual edit was made to some file. i think it was provoked by the piservice shutting down unexpected or some thing.
if that is what happend you may be able to find the old thread somewhere.
running the program vrpathreg.exe in your steam installation folder which per default looks something like this:
C:\Program Files (x86)\Steam\steamapps\common\SteamVR\bin\win64
will tell you where the current active config files are placed
Running vrpathreg opens and quickly closes a window. I have tried modifying the .vrsettings file that exist in both the Steam/config folder and the appdata folder. When I change the file in config folder it overwrites the file. If I set it to read only it creates a .tmp file.
run it from the comand prompt
(click start -> type “cmd” -> right click and chose run as administrator)
then
cd “C:\Program Files (x86)\Steam\steamapps\common\SteamVR\bin\win64”
and then
vrpathreg.exe
weird, steamvr.vrsettings should be the permanent file that will keep your changes and default.vrsettings the one that gets overridden on every steam start. I don’t know what else to suggest.
Unfortunately, those wrong double-quote characters can be hard to notice and many editing systems like to substitute the “pretty” ones (like what just happened on this line). Most programs and computer languages require the use of the ASCII double-quote char.
I noticed in the config file that the quotes looked different, as I said this didn’t solve the problem, just kept Steam from rejecting/overwriting the file.
I have however fixed the problem. I uninstalled/installed SteamVR/PiTool, and updated my graphics driver. I’m not sure which of these fixed it, but I’m not going to question results.