C:\>Users\x\UnrealEngine>GenerateProjectFiles.bat
Setting up Unreal Engine 4 project files...
GenerateProjectFiles ERROR: It looks like you're missing some files that are required in order to generate projects. Please check that you've downloaded and unpacked the engine source code, binaries, content and third-party dependencies before running this script.
To fix, run setup.bat like:
C:\Users\x\prj\UnrealEngine>setup.bat
Note that you have to say no to the prompt Would you like to overwrite your changes (y/n)?.