How to turn off the Windows Defender notification-icon in v1703?

Tried the group policy, tried the direct registry setting, tried the notification-settings - nothing works anymore. Does anyone know the magic trick to turn off the Windows Defender notification-icon?
The icon I am speaking off:

Any ideas?

CWGilley said:

Check out this post Getting rid of the CU "Security Center" taskbar icon?

Thank you for your answer; I need another way though since I'm not using the task manager.

Starhowl said:

Thank you for your answer; I need another way though since I'm not using the task manager.

Why not? It's simple to open Task Manager, just right-click on the taskbar and select it.

You need to be an administrator (or to run Task Manager as an administrator) to be able to disable anything in Start-up. Any other way of removing the icon would also require admin rights, such as running this in a command prompt:
taskkill /im MSASCuiL.exe

Without admin rights, your only alternative is to move the Defender icon into the 'Hidden icons', only visible when you click the up-arrow in the notification area.

Hide or Show Notification Area Icons on Taskbar in Windows 10