Yesterday and the day before, it was widely reported that various Macs couldn’t be updated to the latest version, OS X 10.8.2. The issues were generally vague, and only seemed to affect 2012 models. However, it seemed clear that Apple knew of the issue and was working to get the update out to all users.
That fix is available today in the form of a supplemental update. Apple acknowledges the issue, saying that the update is “is recommended for all Mac systems introduced in 2012″ and that it fixes “an issue with Keychain that can affect 2012 Mac systems.” This supplemental upgrade is bundled with 10.8.2 for anyone who has yet to update to 10.8.2, and is specifically targeted for release to anyone with a 2012 Mac. The latest version of OS X includes the usual bug fixes, alongside improved battery life on notebooks.