This was a design choice by microsoft to maximize protection in server 2016.
Windows server 2016 disable antivirus.
Due to changes from microsoft in the server 2016 architecture windows defender antivirus will not disable itself when other antivirus products are detected.
The need for high level security is one of the priority concerns for it experts and professionals today as emerging new threats coupled with successful and high profile security breaches continue to hit the headlines.
By default microsoft defender antivirus is installed and functional on windows server 2016 and windows server 2019.
When the policy opens for editing click enabled.
When remove features page opens.
Microsoft has also removed api s for other antivirus software to cleanly stop and disable windows defender av.
Enable the user interface on windows server 2016 or 2019.
In server 2016 if you want to use another another antivirus program to protect your server the windows defender will not disable itself as it happens in window 10 in order to maximize the protection in server 2016.
The user interface gui is installed by default on some skus but is not required because you can use powershell or other methods to manage microsoft defender antivirus.
On the details pane of windows defender antivirus node locate and double click turn off windows defender antivirus policy.
In windows 10 windows defender has an api that allows other antivirus programs to disable it to prevent issues.