This question of mine: How do I install Windows Defender/MSE on Server 2012? was closed as a duplicate of Does Microsoft Security Essentials work with Windows Server 2003 R2 SP2?. However, the “main” question talks about Server 2003, while mine talks about Server 2012 and, as I indicated, MSE can be installed on 2008 R2: while it does throw up an error on Server 2012 (sorry, no screenshot for now).
I voted to close that question because of the following:
A question is considered to be a duplicate of another question if it has the same answer. The accepted answer to Does Microsoft Security Essentials work with Windows Server 2003 R2 SP2? indicates that MSE won't work on any server version, and surely enough, Microsft itself says here:
Microsoft Security Essentials is supported on Windows 7, Windows Vista, and Windows XP.
I for once did not know that things had changed. I even followed the link to Microsoft's web site to verify the claim from the accepted answer.
I do now and cast the fifth and final reopen vote.