Error renaming ASP.NET MVC project

Question

I have copied a previous project and renamed it. Once I had successfully renamed all the name spaces and it build correctly. I got the following error when I ran the application:

The following errors occurred while attempting to load the app.
- The OwinStartup attribute discovered in assembly 'User Manager Interface' referencing    startup type 'User_Manager_Interface.Startup' conflicts with the attribute in assembly   'Service Monitor Web Interface' referencing startup type  'Service_Monitor_Web_Interface.Startup' because they have the same FriendlyName ''. Remove or   rename one of the attributes, or reference the desired type directly.
To disable OWIN startup discovery, add the appSetting owin:AutomaticAppStartup with a value of "false" in your web.config.
To specify the OWIN startup Assembly, Class, or Method, add the appSetting owin:AppStartup with the fully qualified startup class or configuration method name in your web.config.

I have figured out that if I comment out the first line below then the error goes away.

//[assembly: OwinStartupAttribute(typeof(Service_Monitor_Web_Interface.Startup))]
namespace Service_Monitor_Web_Interface
{
public partial class Startup
{
    public void Configuration(IAppBuilder app)
    {
        ConfigureAuth(app);
    }
}
}

I renamed my solution from User_Manager_Interface to Service_Monitor_Web_Interface.

I cant seem to find any places with the old name, howevel in the error it mentions it.

Answer 1

I had this issue a few times already, so I will write down the procedure I follow also as a reminder for myself:

1. Replace all of the old solution name with the new one.
2. Navigate to Properties under each project and change the Assembly Name and Default Namespace fields to new solution name.
3. Go to solution folder and rename all project folders with the new solution name.
4. Remove all files under bin and obj folders.
5. Solution will not be able to load projects. Remove all projects and add them again.
6. Re-build the project.