Guys I’m also getting this error. I have created my own user defined packaged which I’m not trying to use in a Library Project. When I go to install my user defined packages, I’m getting the same error NU1202: Package userpackage 1.0.4 is not compatible with net461 (.NETFramework,Version=v4.6.1). Package userpackage1.0.4 does not support any target frameworks.
I have also uninstalled STUDIO and reinstalled but it didn’t fix this issue!