Microsoft update 3004394, aka “December 2014 update for Windows Root Certificate Program in Windows”, “is causing additional problem on computers that are running Windows 7 Service Pack 1 (SP1) and Windows Server 2008 R2 SP1. This includes the inability to install future updates. “

The advisory for 3004394 offers a page called “3024777 You cannot install Windows updates after KB 3004394 is installed on Windows 7 and Windows Server 2008 R2” as the source of a fix.

3024777 is now live.

This is the second screwed update from Microsoft in as many months.