If you try to install Microsoft Security Essentials on Server 2012, you receive an unsupported OS warning.

Solution:

Set MSEinstall to run in Windows 7 compatibility mode. Then go to PowerShell, type the file path followed by /disableoslimit and press Enter. Start the installation.

(mseinstall.exe /disableoslimit)

Regards,
Berk Ozgenc – Sedat Dagci