My PC specs: Intel Xeon CPU E3-1230 V2 @ 3.30GHz 3.30GHz 16 GB RAM memory 64-bit Windows 7 Professional SP1 NVIDIA GeForce GTX 660 Ti DirectX version 11.0 My PC runs fine on Unity 5.2.4 and previous versions. The problem starts when installing Unity 5.3.0, 5.3.1, ... , 5.4.0b2. PROBLEM 1 After installing Unity 5.4.0b2 (same for up to 5.3.0), I start Unity with a new empty project. Unity starts super low, almost hangs there for 5 or 7 minutes. Also, Unity closes super low. At first, it starts with some white areas. Lots of spikes on CPU & Memory usage just to start the Unity & even close the Unity. Unity often "Not Responding" so many times ><. After 5 or 7 minutes, finally Unity opens with a pink Skybox issue. Here is the error messages: Shader compiler: internal error initializing platforms: Protocol error - failed to read correct magic number Shader compiler: internal error compiling shader snippet type=0 platform=4: Failed writing data to socket Shader compiler: internal error compiling shader snippet type=1 platform=4: Failed writing data to socket Shader error in 'Skybox/Procedural': Internal error communicating with the shader compiler process Temporary disable Skybox display from Editor window, and set Camera Clear Flags to Solid Color, can hide the pink Skybox. But, the Skybox compiling issue makes the whole Unity engine too slow & often not responding. I quickly scan through "Editor.log" & "Editor-prev.log". It looks like there are some Shader compiler exceptions. But, I'm totally noob on shading languages to be able to fix it. ANOTHER BUG When I press Play, Unity often hangs. I need to end some "adb.exe * 32" processes in order for the Unity to be able to play the scene. I try to explain as much info as possible. I hope you guys can help me to fix the annoying Shader Compiler exceptions.