using System.Web.Mvc producing errors

Question

After my latest build of my solution, Visual Studio 2017 v15.9.24 started to show multiple errors all pointing to this

The type or namespace name 'Mvc' does not exist in the namespace 'System.Web' (are you missing an assembly reference?)	 

so what do I need to do to fix this?

Answer 1

I just restarted visual studio and the errors went away.