Apple has introduced a software update designed to fix intermittent audio loss issue experienced by some users of the 27-inch LED Cinema Displays.
A previous tech note describes the problem:
“You may notice that sound from an LED Cinema Display (27-inch) connected to a Mac intermittently becomes inaudible. In some circumstances, you may need to unplug the display and reconnect it or restart the Mac before the sound becomes audible again.”
The company says the update addresses these issues. It isn’t a standard update, what happens is the updater application is installed in the Utilities folder after which it should launch automatically. Customers requiring the update should then follow the instructions within the application.