C# – Run a Windows Service as a console app

What's likely happening is that SignalData is indirectly changing the subscribers dictionary under the hood during the loop and leading to that message. You can verify this by changing

foreach(Subscriber s in subscribers.Values)

To

foreach(Subscriber s in subscribers.Values.ToList())

If I'm right, the problem will disappear.

Calling subscribers.Values.ToList() copies the values of subscribers.Values to a separate list at the start of the foreach. Nothing else has access to this list (it doesn't even have a variable name!), so nothing can modify it inside the loop.

In your Installer class, add a handler for the AfterInstall event. You can then call the ServiceController in the event handler to start the service.

using System.ServiceProcess;
public ServiceInstaller()
{
    //... Installer code here
    this.AfterInstall += new InstallEventHandler(ServiceInstaller_AfterInstall);
}

void ServiceInstaller_AfterInstall(object sender, InstallEventArgs e)
{
    ServiceInstaller serviceInstaller = (ServiceInstaller)sender;

    using (ServiceController sc = new ServiceController(serviceInstaller.ServiceName))
    {
             sc.Start();
    }
}

Now when you run InstallUtil on your installer, it will install and then start up the service automatically.