Update This was written for difficulties with deploying an MVC 2 app. I have written a new blog post about deploying an ASP.NET MVC 3 web application to keep you up to date with the new technologies.
When I installed Visual Studio 2010 on my local machine it came with all the fruit included (.NET4 framework, MVC2 etc) so the System.Web.Mvc.dll can be found in my machine's GAC (C:\Windows\assembly). However, since there is no need to bloat the web servers only the plain old .NET4 framework has been installed on the test servers. This does NOT include the MVC assembly and that is why it cannot be found by the web application.
You need this assembly to be on your web servers that you are deploying to but you want to avoid having to copy them into the GAC manually and doing all that
gacutilmess or maybe you don't have access to your servers if they are hosted by godaddy or something.
SolutionYou need to make the
System.Web.Mvcassembly bin deployable... okay that doesn't sound easy but here is how to do it for the necessary MVC references:
Simply right click the reference and select 'Properties':
Then change 'Copy Local' to 'True':
NoteIf your server has .NET 3.5 sp1 installed the new(ish) assemblies System.Web.Routing and System.Web.Abstractions will already be in the GAC. If you had previously deployed an MVC 1 application to a .NET 3.5 server you may remember having to deploy the other two assemblies too. Since MVC2 requires at least .NET 3.5 sp1 you will not need to worry about these assemblies, just