Mac OS X 10.4.5 or later: Headphone volume reverts to default setting after restarting computer
Products Affected
Mac mini (Mid 2007), Mac mini (Late 2006), Mac mini (Early 2006), iMac (20-inch, Mid 2007), iMac (24-inch Mid 2007), iMac (Mid 2006 17-inch), iMac (Early 2006 20-inch), iMac (Early 2006 17-inch), iMac (24-inch, Late 2006), Mac OS X 10.4, iMac (20-inch Late 2006), iMac (17-inch, Late 2006 CD), iMac (17-inch, Late 2006), iMac (24-inch, Early 2008), iMac (20-inch, Early 2008)
Issue or symptom
After restarting in Mac OS X 10.4.5 or later on some Intel-based Macs, the output volume level and balance settings for headphones or other devices connected to your computer's headphone jack may revert to the default settings. The default settings are: Mute is disabled, volume is set to 56% of maximum, and balance is equal for the left and right channels.
Solution
Adjust the volume level and balance as desired after restarting the computer.
This document will be updated as more information becomes available.