im learning UE4 on linux i tried to create a new project but the editor blocked in 96% loading and the terminal show me this error :
LogMaterial: Missing cached shader map for material M_Metal_Copper, compiling.
From my experience shader compilation can be very time consuming especially on Linux / OpenGL. So probably this is not an error, but the shader compilation still need more time to finish. Our project gets stuck as well for some time typically at around 93%.
Issue a top command in your terminal to check if ShaderCompileWorkers are running. Once all shaders are compiled and cached the next editor startups should be much faster.