The OWIN Startup Class is now unavailable.

Problem

This problem occurs because my project is unable to locate the reference for the OWIN starter class. Even after installing all of the OWIN reference packages via Nuget, I’m still having problems. I’m working with MVC4 and Visual Studio 2012.

While attempting to load the program, the following issues occurred.

Asked by Krunal Patil

Solution #1

This will assist you in creating one class with the name Startup.

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

Answered by cracker

Solution #2

We didn’t need OWIN capability in our project, therefore we removed all owin references from the original ASP.NET MVC template project. After eliminating the OWIN starter class, the problem reappeared.

The extra owin dlls in my bin folder were the source of the problem. The issue was remedied when I erased them. By deleting the bin folder, you can get rid of them. These dlls are not deleted by Clean Solution.

Even if the OWIN dlls are in the bin folder, IIS still executes them.

Answered by Hüseyin Yağlı

Solution #3

There is a template for this in Visual Studio 2013 RC2. Simply place it in the App Start folder.

The template generates a class like this:

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 } } }

Answered by Timuçin

Solution #4

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

Add the following line under AppSettings:

    <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>

Answered by Yonatan Ayalon

Solution #5

Look for the Startup.cs file; it’s possible that you’re missing one. This file is the starting point for OWIN, therefore it appears to be missing. To get a better idea of what’s going on, take a look at the OWIN Startup class.

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

Answered by Christian Phillips

Post is based on https://stackoverflow.com/questions/20068075/owin-startup-class-missing