SignalR no longer working "No assembly found containing an OwinStartupAttribute"
asp.net, asp.net-web-api, owin, signalr
Solution
I had this error during Identity Framework 2.0 integration. Adding Following in Web.config file of the project solved it:
<appSettings>
<add key="owin:AutomaticAppStartup" value="false" />
</appSettings>
Problem
I have a Web API project that uses SignalR which started giving me "unable to find Microsoft.AspNet.Signal.Core" errors frequently which were only fixed by doing a full rebuild in Visual Studio. I upgraded SignalR and OWIN in Nuget to try and fix this issue, but now I always get "The following errors occurred while attempting to load the app. - No assembly found containing an OwinStartupAttribute. - No assembly found containing a Startup or [AssemblyName].Startup class" I am the only person on my team to get this error - the same code works fine on other machines. I have a Startup Class: ``` using System; using System.Collections.Generic; using System.Linq; using System.Web; using Microsoft.Owin; using Owin; [assembly: OwinStartup(typeof(MyProject.Startup))] namespace MyProject { public class Startup { public void Configuration(IAppBuilder app) { app.MapSignalR(); } } } ``` I have tried adding the AppStartup key to the web.config too: ``` <add key="owin:appStartup" value="MyProject.Startup, MyProject" /> ``` I have the following references in my WebApi project: ``` Microsoft.AspNet.SignalR.Core (2.1.0.0) Microsoft.AspNet.SignalR.SystemWeb (2.1.0.0) Microsoft.Owin (2.0.2.0) Microsoft.Owin.Host.SystemWeb (2.0.2.0) Microsoft.Owin.Security (2.0.2.0) Owin (1.0.0) ``` I'm using IIS 8.5 on Windows 8 64Bit