The Carbon Sound Manager Update 6.0.2, a component of QuickTime 6, improves reliability and performance of some applications that access Carbon Sound Manager. It is available through the Software Update pane of System Preferences. If the version of QuickTime 6 you installed does not require the update, it will not appear in the list of available updates. You only need to install the Carbon Sound Manager Update if it appears in the Software Update pane. This update is not necessary with QuickTime 6.1 or later.