Windows Defender is a free anti-spyware and spyware scanning and removal tool that protects computer against pop-ups, slow performance, and security threats caused by spyware, adware and other unwanted software in real-time. Previously Windows Defender is called Microsoft Anti-Spyware and after installing Microsoft Anti-Spyware, there will be an icon in the notification area (system tray).
However, in Windows Defender, you won’t be able to see or find any Windows Defender’s icon resided in notification area or system tray, as the icon is not enabled by default. That’s mean Windows Defender icon will be missing from Windows system tray unless you specifically select the option to display the Windows Defender icon.
To display the Windows Defender icon in Windows notification area (system tray), go to Tools and select Options under the Settings section. Scroll down the Options page, at the section of “Real-time protection options”, there is an option “Choose when the Windows Defender icon appears in notification area“. By default the selected option is “Only if Windows Defender detects an action to take”, which means the icon will only appear if there is any action by Windows Defender. To always show the Windows Defender icon, select (check) “Always“. Click on Save when done.