This happens intermittently with Windows 10 updates- either Norton Security or Norton VPN disappears from the task bar. This is because Windows 10 updates sometimes stops Norton products from running due to Mocrosoft's desire to cotrol every aspect of your art buttoncomputer. It just happened to me today. Just right click the start button, or hold down the Windows button and click the letter "r" and run services.msc. You will find that Norton Security or Norton VPN are still set to automatic, but are no longer running. Right click either item and click Start and they will reappear on your task bar.