If your using the AirServer product - www.airserver.com - to mirror an IOS device on Mac desktop.
You should know that the AirServer uses port 5000 as does the Xamarin Build Host.
On Reboot the AirServer will usually grab the port before the Xamarin Build Host does. This will stop you from compiling until the AirServer is stopped. This will result in hours of troubleshooting fun. If your really determined to be productive, you can expect hours of cursing and hair pulling way into the night.
Best thing to do is to uncheck the AirServer Preference "Launch On Start-up" and do it manually. I dont know anyway of changing the port it uses.
It would be nice if the Build Host had an activity indicator so you could tell if the Build Host was able to bind to port 5000.