Having issue with multiple controllers of the same name in my project

The error message contains the recommended solution: "If this is the case, register this route by calling an overload of the 'MapRoute' method that takes a 'namespaces' parameter."

routes.MapRoute(
     "Default", // Route name
     "{controller}/{action}/{id}", // URL with parameters
     new { controller = "Home", action = "Index", id = UrlParameter.Optional }, // Parameter defaults
     new string[] { "MyCompany.MyProject.WebMvc.Controllers"}
);

This will make http://server/ go to your HomeController's Index action which is, I think, what you want. http://server/company/home will go to the Company area's HomeController's Index action, as defined in the area registration.

If you're using RazorGenerator, just informing the namespaces parameter could be not enough.

I got to solve adding the statement marked below at Global.asax.cs:

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
        ControllerBuilder.Current.DefaultNamespaces.Add("MyProject.Controllers"); // This one
    }

This is the asp.net mvc4 approach:

 routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "RegisterNow", id = UrlParameter.Optional },
            namespaces: new[] { "YourCompany.Controllers" }
        );

I had renamed the namespaces, so, i only delete de folders bin and obj and rebuild, work again.