- Try to recreate the shaders, by removing these folders while the simulator is not running:
%LOCALAPPDATA%\Lockheed Martin\Prepar3D v4\Shaders
Start the sim, wait a minute ( with a black screen, it's normal, don't panic ) until all the objects will eventually come back.
- If you updated to P3D4.5 using only the Client, PBR won't work correctly. You must update the Content too.