Hans Vredevoort has posted a very important note for you to read. Please go over to Hyper-v.nu to read why you should not install this update on WS2012 clusters nodes/members.
EDIT#1:
Microsoft has released (via Windows Update) KB2803748 to repair this issue.
Holy hell, this killed my entire day yesterday!!! I’ve actually just refinished reformatting both the servers in my cluster because I couldn’t figure out how to fix this. At least I know I’m not crazy…
@jake, hope it wasn’t your production environment.
Crazy that MS didn’t make this simple test step in pre patch testing.