Why do I get a warning icon when I add a reference to an MEF plugin project?

Question

I wish to test the core class of a plugin by directly referencing the plugin project and instantiating the plugin class. When I create a test Console App project and add a p

Answer 1

I had created a new .sln which was put in a subfolder. The .nuget folder was missing from where that .sln file was added. Moving the .nuget folder from the root into the subfolder where my new .sln file was solved the issue for me.

I came back later and added the .sln file to the root and deleted the subfolder. Doing this originally would have solved the issue as well.