Apple has issued a supplemental update for version 10.8.2 of OS X, which addresses a few problems users are having with the way the OS handles the Keychain in some systems. The update is for Macs issued in 2012, and is a small 26.65MB download that will apply new versions of the SecurityAgent process and its supporting daemons and configuration files.
SecurityAgent is a background process that implements protocols for accessing certificates, keychains, and other security measures in OS X, and provides interface elements for user interaction with these, including dialog boxes that prompt for usernames and passwords so an application can run with escalated privileges.
This update is only a supplemental updater that addresses problems users are having with current OS installations, and does not fix a current issue in which 2012 Mac Mini and MacBook users cannot seem to install the latest 10.8.2 update altogether.
As we recently reported, a number of users are encountering an error that states "Error: OS X Update can't be installed on this disk. This volume does not meet the requirements for this update" when attempting to run the latest Delta or Combo updaters for OS X on these systems.
It appears this problem may be from Apple having pulled a unique updater for these systems, but this latest supplemental update is not intended to address this issue. This update is only for those who have successfully installed OS X 10.8.2 on their systems, and its purpose is to address keychain-related problems with the update.
For those still experiencing problems when trying to install OS X 10.8.2, it appears you will have to continue to wait for Apple to address the issue.
For those who have OS X 10.8.2 installed on a 2012 Mac system, this latest supplemental update will be available through Apple's Software Update service and will be a quick patch for keychain and certificate-handling problems. You can also download the updater from Apple's update Web page and apply it manually.
As always, be sure to back up your system before applying this or any other software update. Use Time Machine to manually create a fully restorable backup of the system if you do not already have it set to do so on a regular basis. The updater will replace several core service applications and support files, and may require a restart when applied.