Preview rendering level shader model 4 vs 5

Hi everyone,

i have an issue here ,when i’m on shader model 5 the scene is almost black ,but if i turn into shader model 4 everything is clear ,idon’t know why???.

So my question is how to configure UE4 to start up with shader model 4 always ???.

Thank you for your continuous support.

Best regards,

Pictures showing black shading covering the scene when using Shader model 5.