The issue started after shutting down this server to apply updates. It hung on 2 of 52 for several hours. So, I browsed to the C drive and grabbed the CBS.log and the WindowsUpdate.log, crossed my fingers, and rebooted the server.
Then I received a BSOD that read: PROCESS1_INITIALIZATION_FAILED - STOP 0x0000006B
I can only boot to System Recovery Options.
Some quick searching brought me to KB981833 which describes my issue but my system already has SP1, and renaming bootcat.cache and rebooting didn't have any effect.
I have not used the CBS.log or the WindowsUpdate.log to troubleshoot failed updates much, but I think this excerpt from the CBS.log may help:
2013-08-30 20:34:12, Info CBS Read out cached package applicability for package: Package_for_KB2786081~31bf3856ad364e35~amd64~~6.1.1.0,
ApplicableState: 112, CurrentState:0
2013-08-30 20:34:12, Info CBS Session: 30320114_2482747204 initialized by client WindowsUpdateAgent.
2013-08-30 20:34:12, Info CBS Failed to internally open package. [HRESULT = 0x800f0805 - CBS_E_INVALID_PACKAGE]
2013-08-30 20:34:12, Info CBS Session: 30320114_2482757925 initialized by client WindowsUpdateAgent.