Look at the bottom-right corner of your Windows screen, or the top-right on a Mac (next to the clock). See those tiny little icons? Those are tray icons—and they’re some of the hardest-working, yet most overlooked, elements of your computer’s interface.
Sometimes a program crashes and relaunches, leaving a "ghost" icon.
Solutions:
ie4uinit.exe -show command (Windows 10) to reset icon cache.When you click the X on a program window, it might not actually quit. It often just hides the window and keeps running in the tray.
To fully exit, you usually need to right-click the tray icon and choose Exit or Quit.
Example:
When you click the minimize or close button on certain applications (like Slack, Discord, Spotify, or backup software), they do not exit. Instead, they "hide" down to the system tray. The tray icon remains live, allowing you to restore the window with a double-click or right-click to exit fully.
The icon is visible, but clicking or right-clicking does nothing. what is a tray icon
Solutions:
sfc /scannow in Command Prompt as admin).