Here is a guide on how to fix the “D3DX Compile Failed” Error at game launch.
D3DX Compile Failed – Fix
The cause for the “FATAL ERROR in Vertex Shader compilation” on the game launch are outdated DirectX drivers. To fix the issue, you can either update your PC’s DirectX drivers (I) or turn off the shaders from the game files (II). The affect of the shaders on the gameplay are minimal.
[Also, since it’s still unclear on how many people are actually getting the error, please feel free to leave a comment below so I can get some data on the subject. Thank you! -Dev]
I – Updating DirectX Drivers
Simply, download and run the installer you can get from the link below.
Driver Update [www.microsoft.com]
II – Turning off Shaders
Step I – Search for %LOCALAPPDATA% and open the folder.
Step II – Find the “Shadowrain” folder and open it
Step III – Open the Options.sav file in for example notepad
Step IV – Change the shader value (highlighted) from 1 (on) to 0 (off)