I have VS 2015 and VS 2017 installed side by side on Windows 10. The scaffolding works from VS 2015. If I run the same command from VS 2017 (e.g. Scaffold SysManager.ScaffoldBackend.For SpUdf5) then I see no errors and nothing gets generated at all. Some other developers in our team who only installed VS 2017 Enterprise are able to generate output, but not all of them. We could not figure out the common denominator between working and non-working environments.