updated 04:42 pm EST, Tue November 20, 2012
Targets Keychain problem
Apple has released a new software update, OS X Mountain Lion 10.8.2 Supplemental Update 2.0. The code fixes the issues behind an earlier release, and should let the 2012 Mac mini, 13-inch Retina MacBook Pro, and 2012 iMac properly upgrade to v10.8.2. "This update addresses an issue with Keychain that can affect 2012 Mac systems," Apple's notes read.
It's relatively rare for Apple to pull software updates. The company usually tests each one thoroughly, and often any new glitches can be fixed in a subsequent update. Supplemental Update 2.0 is a 26.65MB download.