How do I install Windows Defender/MSE on Server 2012?
Solution 1:
I set the compatibility mode for the installer to Windows 7 and then started it with the /disableoslimit
command line parameter.
Solution 2:
Currently the answer is "It's not supported on Server operating systems", as Microsoft doesn't list Server (2012) as a supported OS.
From MS' MSE requirements page:
Microsoft Security Essentials is free* and easy to download and use. Here's what you need to run it:
Operating System: Windows XP Service Pack 3 (SP3); Windows Vista (Service Pack 1, or Service Pack 2); Windows 7*
As with previous versions you may be able to unofficially install them at some point, but for now, it's not compatible.