Keep getting a 405 error (no gpu supporting d3d10_feature_level_9_1); this is the guide for you! After hours of research I finally found the solution.
This was on GeForce GTX 1060 that runs DX12 using Oculus Rift system.
As far as I can tell, the issue is between DX11 and DX12 when starting SteamVR. When you open up SteamVR it may be trying to start in Full Screen mode, but it is better to run it windowed; don't worry, the Oculus Rift will function properly and run the game.
After attempting to install multiple drivers, the same issue persisted.
Things I tried:
- Running Steam as an administrator, did not fix it
- Rolling back drivers, didn't fix it
- Completely reinstalling drivers, did not fix it
- Changing DX11 on SteamVR
The solution I stumbled upon. Add this to Steam VR Launch Property:
-w 1920 -h 1080 -full -novid -high -threads 4 -nojoy +cl_forcepreload 1 -nod3d9ex
*Ensure you change the -w and -h to your monitor resoultion.