The type or namespace IAppBuilder could not be found(missing using a directive pr an assembly reference)

Question

I am working on an Asp.Net MVC 4 Application in which I am using SignalR 2.0.1 and I Mapped it using Owin Startup class and it worked fine at first.

All of a sudden

Answer 1

http://www.asp.net/signalr/overview/getting-started/tutorial-getting-started-with-signalr

Check for the visual studio you are using You can find the following comment

Note: If you are using Visual Studio 2012, the SignalR Hub Class (v2) template will not be available. You can add a plain Class called ChatHub instead.

Also Note: If you are using Visual Studio 2012, the OWIN Startup Class template will not be available. You can add a plain Class called Startup instead.