Visual studio 2019 go to definition and Intellisense not working

Question

I have noticed a weird issue with Visual Studio 2019 v16.0.1 the IntelliSense about \"Using directive is unnecessary\" normally grey is missing and type reference suggestion

Answer 1

I tried lots of things but nothing worked for me until I found this post. He mentions a few things I have already tried that didn't work, but his final solution worked for me...

At the root of our solution there is a packages folder. I deleted the entire contents of this folder. Upon reopening Visual Studio, Intellisense and Go To Definition were restored to full working order.