UnrealBuildTool Exception: System.IO.Directory

Hello guys,
I am trying to compile UE4.8 on Ubuntu on my external hard drive. All dependencies are installed and
Setup.sh finished with success, but I receive an error on ./GenerateProjectFiles.sh

Terminal Output:


For me it looks like it is only looking in the wrong directories. I can find the files manually in UnrealEngine/Engine/Documentation/…

How can I fix this?

What filesystem do you have on that drive? It looks like mono has a problem with it.

The Hard Drive is formatted in “ext4 version 1.0”

Should I use another filesystem? Or is there any script where I can fix the paths manually?