title: A route named 'Billing_Default' is already in the route collection. Route names must be unique. Parameter name: name
body: <p>Deleted bin folder and also have cleaned and rebuilt multiple times. For some reason after checking all the required files where routes get configured I am running into the naming error, I changed it and manuplated it to my best extent, but I am stuck. I am trying to learn asp.net, but this error has me dumbfounded. </p>
  
  <p>This is folder system, I have expanded the important ones:</p>
  
  <pre><code>Project-
     Reference-
     Packages-
     App_Start-
         -RouteConfig.cs
         -WebApiConfig.cs
     Areas-
         -Billing
         -Invoice
     Content-
     Controllers-
     Models-
     Scripts-
     Views-
     Global.asax
     Pacages.config
     Web.config
  </code></pre>
  
  <p>I have a registration file in each of my Areas.</p>
  
  <p>Here is the registration code form one of the Areas.</p>
  
  <pre><code>using System;
  using System.Web.Mvc;
  
  namespace WORK_GODDAMN.Areas.Billing
  {
  
      public class BillingAreaRegistration : AreaRegistration
      {
          public override string AreaName
          {
              get
              {
                  return "Billing";
              }
          }
  
          public override void RegisterArea(AreaRegistrationContext context)
          {
              context.MapRoute(
                  "Billing_default",
                  "Billing/{controller}/{action}/{id}",
                  new { action = "Index", id = UrlParameter.Optional }
              );
          }
      }
  
  
  
  }
  </code></pre>
  
  <p>Here is my Global.asax code</p>
  
  <pre><code>using System.Web;
  using System.Web.Mvc;
  using System.Web.Routing;
  using System.Web.Http;
  
  namespace WORK_GODDAMN
  {
      public class Global : HttpApplication
      {
          protected void Application_Start()
          {
              AreaRegistration.RegisterAllAreas();
              GlobalConfiguration.Configure(WebApiConfig.Register);
              RouteConfig.RegisterRoutes(RouteTable.Routes);
          }
      }
  }
  </code></pre>
  
  <p>Here is my routeConfig code</p>
  
  <pre><code>using System.Web.Mvc;
  using System.Web.Routing;
  
  namespace WORK_GODDAMN
  {
      public class RouteConfig
      {
          public static void RegisterRoutes(RouteCollection routes)
          {
              routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
  
              //AreaRegistration.RegisterAllAreas();
  
              routes.MapRoute(
                  name: "Default",
                  url: "{controller}/{action}/{id}",
                  defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
                  namespaces: new string[] { "Core.Controllers" }
              );
  
          }
      }
  }
  </code></pre>
  
  <p>cshtml code for the Index Page which should redirect to the predefined Areas.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  
  &lt;html&gt;
      @using System.Web.Optimization
  &lt;head&gt;
      &lt;meta charset="utf-8" /&gt;
      &lt;meta name="viewport" content="width=device-width" /&gt;
      &lt;title&gt;@ViewBag.Title&lt;/title&gt;
      @Scripts.Render("~/Scripts/modernizr.js")
  &lt;/head&gt;
  &lt;body&gt;
      &lt;div&gt;
          &lt;div&gt;
              &lt;h2&gt;{Demo}- Pluggable Modules&lt;/h2&gt;
          &lt;/div&gt;
          &lt;div id="nav"&gt;
              @Html.ActionLink("Home","Index","Home", new {Area=""}, null) |
              @Html.ActionLink("Marketing","Index","Marketing", new {Area="Marketing"}, null) |
              @Html.ActionLink("BillingMain", "Index", new { Area = "Billing" })
          &lt;/div&gt;
          &lt;hr /&gt;
          &lt;div&gt;
                  @RenderBody()
          &lt;/div&gt;
      &lt;/div&gt;
      @Scripts.Render("~/Scripts/jquery.js")
      @RenderSection("Scripts", required: false)
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>I am not why this confliction is happening, I have cleaned and rebuilt multiple times, I am using 2017 Mac Visual Studio so I had to configure Areas myself. </p>