Disable Windows Defender on Windows Server 2016 or later
The Deep Security Anti-Malware module is not supported for use with anti-malware products from other vendors. This includes Windows Defender, which is installed by default on Microsoft Windows Server 2016 and later. To use Deep Security Anti-Malware, you must disable Windows Defender before installing the Deep Security Agent.
Microsoft Windows Defender requires a computer reboot to complete its deactivation.
If you don't disable Windows Defender before installing Deep Security Agent, the agent installation process will disable it. However, the agent installation process does not perform the computer reboot that's required to complete the disabling of Windows Defender. The agent will report a computer warning event ("A computer reboot is required to enable Deep Security Agent protection") to the Deep Security Manager. This event is cleared when you reboot the computer.