title: CS0234 The type or namespace name 'Owin' does not exist in the namespace 'Microsoft'
body: <p>I'm using VS 2015 Community and attempting to create a WebServer Console using these "simple" tutorials:</p>
  
  <p><a href="http://dotnetcodr.com/2014/04/14/owin-and-katana-part-1-the-basics/" rel="nofollow">OWIN and Katana part 1: the basics</a></p>
  
  <p><a href="http://pluralsight.com/training/Player?author=scott-allen&amp;name=aspdotnet-mvc5-fundamentals-m2-katana&amp;mode=live&amp;clip=0&amp;course=aspdotnet-mvc5-fundamentals" rel="nofollow">ASP.NET Fundamentals</a></p>
  
  <p>Both tutorials seem easy enough, however, I pretty much get stuck at the same spot when I try to compile them.  Both tutorials reference <strong>DNX 4.5.1</strong> (Microsoft.Owin.Host.HttpListener (3.0.1) and Microsoft.Owin.Hosting (3.0.1)) &amp; <strong>DNX Core 5.0</strong>.  Here is the code from the first link (which is almost identical (including errors) to the second link so I will not include that code):</p>
  
  <pre><code>using Microsoft.Owin.Hosting;
  using Owin;
  using System;
  
  namespace KatanaBasics
  {
    public class Program
      {
          public static void Main(string[] args)
          {
            string uri = "http://localhost:7990";
  
            using (WebApp.Start&lt;startup&gt;(uri))
            {
              Console.WriteLine("Web server on {0} starting.", uri);
              Console.ReadKey();
              Console.WriteLine("Web server on {0} stopping.", uri);
            }
          }
      }
  
      public class startup
    {
        public void Configuration(IAppBuilder appBuilder)
        {
          appBuilder.Run(owinContext =&gt;
          {
            owinContext.Response.WriteAsync("Hello from OWIN web server");
          });
        }
    }
  }
  </code></pre>
  
  <p>I get the red squiggly lines starting at <strong>owinContext =></strong> and it continues till the end of the method.
  And here are the errors I get when I try to compile:</p>
  
  <pre><code>Severity    Code    Description Project File    Line    Suppression State
  Error   CS0234  The type or namespace name 'Owin' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)  KatanaBasics.DNX Core 5.0
  
  Severity    Code    Description Project File    Line    Suppression State
  Error   CS0246  The type or namespace name 'Owin' could not be found (are you missing a using directive or an assembly reference?)  KatanaBasics.DNX Core 5.0
  
  Severity    Code    Description Project File    Line    Suppression State
  Error   CS0246  The type or namespace name 'IAppBuilder' could not be found (are you missing a using directive or an assembly reference?)   KatanaBasics.DNX Core 5.0
  
  Severity    Code    Description Project File    Line    Suppression State
  Error   CS0103  The name 'WebApp' does not exist in the current context KatanaBasics.DNX Core 5.0   
  
  Severity    Code    Description Project File    Line    Suppression State
  Error   CS1643  Not all code paths return a value in lambda expression of type 'Func&lt;IOwinContext, Task&gt;'   KatanaBasics.DNX 4.5.1
  </code></pre>
  
  <p>Owin is not in DNX Core 5.0 but it is in DNX 4.5.1.  I thought maybe I could move or copy to DNX 4.5.1 but it seems DNX Core 5.0 is where it wants to default.</p>
  
  <p>I have found resolutions to similar problems but I do not understand all the explanations.  For instance I read one post that said to change targets, however, I couldn't even find anything like what or where they described to "fix" it.  So, it seems maybe I need an earlier of DNX Core 5.0?  If so, how do I reference an earlier version?  Thanks much!</p>