diff --git a/src/Umbraco.Tests/Routing/RenderRouteHandlerTests.cs b/src/Umbraco.Tests/Routing/RenderRouteHandlerTests.cs
index 5bdd0bac75..b52a560d47 100644
--- a/src/Umbraco.Tests/Routing/RenderRouteHandlerTests.cs
+++ b/src/Umbraco.Tests/Routing/RenderRouteHandlerTests.cs
@@ -74,7 +74,9 @@ namespace Umbraco.Tests.Routing
 
 			handler.GetHandlerForRoute(routingContext.UmbracoContext.HttpContext.Request.RequestContext, docRequest);
 			Assert.AreEqual("RenderMvc", routeData.Values["controller"].ToString());
-			Assert.AreEqual("Index", routeData.Values["action"].ToString());
+            //the route action will still be the one we've asked for because our RenderActionInvoker is the thing that decides
+            // if the action matches.
+            Assert.AreEqual("homePage", routeData.Values["action"].ToString());
 		}
 
 		//test all template name styles to match the ActionName
diff --git a/src/Umbraco.Tests/Stubs/TestControllerFactory.cs b/src/Umbraco.Tests/Stubs/TestControllerFactory.cs
index 98bedaa078..872093f896 100644
--- a/src/Umbraco.Tests/Stubs/TestControllerFactory.cs
+++ b/src/Umbraco.Tests/Stubs/TestControllerFactory.cs
@@ -3,6 +3,7 @@ using System.Linq;
 using System.Reflection;
 using System.Web.Mvc;
 using System.Web.Routing;
+using System.Web.SessionState;
 using Umbraco.Core;
 
 namespace Umbraco.Tests.Stubs
@@ -28,12 +29,12 @@ namespace Umbraco.Tests.Stubs
 
 		public System.Web.SessionState.SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
 		{
-			throw new NotImplementedException();
+			return SessionStateBehavior.Disabled;
 		}
 
 		public void ReleaseController(IController controller)
 		{
-			throw new NotImplementedException();
+			controller.DisposeIfDisposable();
 		}
 	}
 }
\ No newline at end of file
diff --git a/src/Umbraco.Web/Mvc/ControllerFactoryExtensions.cs b/src/Umbraco.Web/Mvc/ControllerFactoryExtensions.cs
new file mode 100644
index 0000000000..86f24ac452
--- /dev/null
+++ b/src/Umbraco.Web/Mvc/ControllerFactoryExtensions.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Web.Mvc;
+using System.Web.Routing;
+
+namespace Umbraco.Web.Mvc
+{
+    internal static class ControllerFactoryExtensions
+    {
+        /// <summary>
+        /// Gets a controller type by the name
+        /// </summary>
+        /// <param name="factory"></param>
+        /// <param name="requestContext"></param>
+        /// <param name="controllerName"></param>
+        /// <returns></returns>
+        /// <remarks>
+        /// This is related to issue: http://issues.umbraco.org/issue/U4-1726. We already have a method called GetControllerTypeInternal on our MasterControlelrFactory,
+        /// however, we cannot always guarantee that the usage of this will be a MasterControllerFactory like during unit tests. So we needed to create
+        /// this extension method to do the checks instead.
+        /// </remarks>
+        internal static Type GetControllerTypeInternal(this IControllerFactory factory, RequestContext requestContext, string controllerName)
+        {
+            var controllerFactory = factory as MasterControllerFactory;
+            if (controllerFactory != null)
+            {
+                return controllerFactory.GetControllerTypeInternal(requestContext, controllerName);                
+            }
+
+            //we have no choice but to instantiate the controller
+            var instance = factory.CreateController(requestContext, controllerName);
+            if (instance != null)
+            {
+                return instance.GetType();            
+            }
+            return null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Umbraco.Web/Mvc/MasterControllerFactory.cs b/src/Umbraco.Web/Mvc/MasterControllerFactory.cs
index 4a58fb7251..100b192bf8 100644
--- a/src/Umbraco.Web/Mvc/MasterControllerFactory.cs
+++ b/src/Umbraco.Web/Mvc/MasterControllerFactory.cs
@@ -9,7 +9,7 @@ using Umbraco.Core;
 
 namespace Umbraco.Web.Mvc
 {
-	/// <summary>
+    /// <summary>
 	/// A controller factory which uses an internal list of <see cref="IFilteredControllerFactory"/> in order to invoke 
 	/// different controller factories dependent upon their implementation of <see cref="IFilteredControllerFactory.CanHandle"/> for the current
 	/// request. Allows circumvention of MVC3's singly registered IControllerFactory.
@@ -70,7 +70,11 @@ namespace Umbraco.Web.Mvc
                 }
                 //we have no choice but to instantiate the controller
                 var instance = factory.CreateController(requestContext, controllerName);
-                return instance.GetType();
+                if (instance != null)
+                {
+                    return instance.GetType();    
+                }
+                return null;
             }
 
             return base.GetControllerType(requestContext, controllerName);
diff --git a/src/Umbraco.Web/Mvc/RenderRouteHandler.cs b/src/Umbraco.Web/Mvc/RenderRouteHandler.cs
index c7ab7a9ee0..5569fa9a92 100644
--- a/src/Umbraco.Web/Mvc/RenderRouteHandler.cs
+++ b/src/Umbraco.Web/Mvc/RenderRouteHandler.cs
@@ -259,7 +259,7 @@ namespace Umbraco.Web.Mvc
             }
 
 			//check if there's a custom controller assigned, base on the document type alias.
-            var controllerType = ((MasterControllerFactory)_controllerFactory).GetControllerTypeInternal(requestContext, publishedContentRequest.PublishedContent.DocumentTypeAlias);
+            var controllerType = _controllerFactory.GetControllerTypeInternal(requestContext, publishedContentRequest.PublishedContent.DocumentTypeAlias);
             
 			//check if that controller exists
 		    if (controllerType != null)
diff --git a/src/Umbraco.Web/Umbraco.Web.csproj b/src/Umbraco.Web/Umbraco.Web.csproj
index 22238d67e7..5c3682e108 100644
--- a/src/Umbraco.Web/Umbraco.Web.csproj
+++ b/src/Umbraco.Web/Umbraco.Web.csproj
@@ -300,6 +300,7 @@
     <Compile Include="DefaultPublishedMediaStore.cs" />
     <Compile Include="Dictionary\UmbracoCultureDictionary.cs" />
     <Compile Include="Dictionary\UmbracoCultureDictionaryFactory.cs" />
+    <Compile Include="Mvc\ControllerFactoryExtensions.cs" />
     <Compile Include="Mvc\SurfaceRouteHandler.cs" />
     <Compile Include="Mvc\UmbracoAuthorizeAttribute.cs" />
     <Compile Include="Mvc\UmbracoAuthorizedController.cs" />