Dev Dev - 2 months ago 3x
C# Question

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

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 when I tried to rebuild my app it said that the type are namespace

could not be found.

Following is my start up class

using Microsoft.Owin;
using Owin;
using WhiteBoardApp;

namespace WhiteBoardApp
public class Startup
public void Configuration(IAppBuilder app)

I have installed
package too, and for some reasons I could not find Owin Startup class so I just added a normal class and included all the references that are needed.
May I know where I am making a mistake


Try to use Package Manage Console and do

Update-Package Owin -Reinstall