If any of these system icons are missing or disappearing from the notification system tray in Windows system, users can easily make these invisible hidden icons to unhide and appear visible again in the Windows Taskbar’s notification area. In Windows notification area (previously known as system tray or simply systray) at the end of the Taskbar, there are always a few system icons that show statuses and allow adjustment control of various system components, such as clock, network connections, sound volume and battery power.