.net – Could not load file or assembly ‘Antlr3.Runtime (1)’ or one of its dependencies

1. Check if you are referencing an assembly which in turn referencing an old version of unity. For example let's say you have an assembly called ServiceLocator.dll which needs an old version of Unity assembly, now when you reference the ServiceLocator you should provide it with the old version of Unity, and that makes the problem.

2. May be the output folder where all projects build their assemblies, has an old version of unity.

You can use FusLogVw to find out who is loading the old assemblies, just define a path for the log, and run your solution, then check (in FusLogvw) the first line where the Unity assembly is loaded, double click it and see the calling assembly, and here you go.

Quite a few ways to fix this:

1. Install MVC on the web server (which is not always possible).

2. In visual studio you can set dlls to copy to local on build, see the following article (please note MVC dlls have changed names slightly but it gives you the process) http://haacked.com/archive/2008/11/03/bin-deploy-aspnetmvc.aspx

3. Copy the appropriate dlls from your GAC into the bin folder of the umbraco site. To do this open "%windir%\Microsoft.NET\assembly\GAC_MSIL" in explorer and you will find all of the dlls installed in the GAC and you can copy the appropriate versions into your project. This is similar to the above method but bypasses building the project.

In terms of files you will likely need more than just System.Web.Razor.dll however this will work for all of the missing files.