OWIN Startup Class Missing

Create One Class With Name Startup this will help you..

public class Startup
{
   public void Configuration(IAppBuilder app)
   {
      app.MapSignalR();
   }
}

In our project, we didn't need the OWIN functionality, so we removed all the owin references from the initial ASP.NET MVC template project. The problem occured after removing the OWIN startup class.

The problem was the extra owin dll's in my bin folder. When I deleted them, the problem was resolved. You should delete them by deleting the bin folder. Clean Solution does not delete these dlls.

Somehow, IIS still executes the OWIN dll's when they are in the bin folder.

On Visual Studio 2013 RC2, there is a template for this. Just add it to App_Start folder.

The template produces such a class:

using System;
using System.Threading.Tasks;
using Microsoft.Owin;
using Owin;

[assembly: OwinStartup(typeof(WebApiOsp.App_Start.Startup))]

namespace WebApiOsp.App_Start
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=316888
        }
    }
}

If you don't want to use the OWIN startup, this is what you should add to your web.config file:

Under AppSettings add the following line:

    <add key="owin:AutomaticAppStartup" value="false" />

This is how it should look like in your web.config:

  <appSettings>
    <add key="owin:AutomaticAppStartup" value="false" />
  </appSettings>

Have a look for the Startup.cs file, you might be missing one of these. This file is the entry point for OWIN, so it sounds like this is missing. Take a look at OWIN Startup class here to understand whats going on.

As your error specifies, you can disable this in the web.config by doing the following...

To disable OWIN startup discovery, add the appSetting owin:AutomaticAppStartup with a value of "false" in your web.config