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

Try closing and opening VS.

Seems silly but after 1 hour of following the above and finding everything lined up OK. I restarted VS 2017 and the problems were gone.