Site stopped working in asp.net System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to

Question

I have a problem like this on server

[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to [B]System.Web.WebPages.Razor.Configuration

Answer 1

In the root Web.config make sure assemblyBinding contains the proper version for the assembly "System.Web.WebPages.Razor" and "System.Web.Mvc". Check for their actual existence as well as my "System.Web.WebPages.Razor" assembly tag was missing causing the error. I had my assembly versions set to 3.0 and 5.0 respectively in the time of this writing with full NuGet updates. Code should look something like below. The publicKeyToken will stay the same between the versions. Cheers!