MVC Razor view Intellisense broken in VS 2013/2015/2017

Question

I have an existing project written in VS2010 which when loaded in VS2010 works perfectly.

When I load this same project in VS2013 the MVC Razor views contain lots of

Answer 1

In upgrading from MVC 3 to 5, I found that in my root directory Web.config that the appSettings key webpages:version was set to 2.0.0.0. Changing this to 3.0.0.0 fixed this issue.