Mac OS 9.2: iTunes and Volume Control Using the Apple Pro Keyboard Volume Keys

This article explains how the Apple Pro Keyboard volume keys work in conjunction with iTunes and system volume with Mac OS 9.2 and later
Symptom

The system volume does not change when using the Apple Pro Keyboard volume keys, only iTunes volume changes.

Solution

This is normal. When iTunes is open, iTunes controls the volume keys. You can change the volume in iTunes, but not the system volume.

Quitting iTunes allows the system volume to be changed using the keyboard volume keys.
Published Date: Feb 18, 2012