Power Mac G5 (Late 2005), iMac G5 (Ambient Light Sensor): FireWire bus stops responding after computer restarts with FireWire audio device attached

This article has been archived and is no longer updated by Apple.

Issue or symptom

If a FireWire audio device is connected to a Power Mac G5 (Late 2005) or an iMac G5 (Ambient Light Sensor) while the computer is restarting, the FireWire bus will stop responding and no FireWire devices will be detected on the bus. The device may stop responding or stop charging, depending on the specifics of the device.

Products affected

  • FireWire device
  • Power Mac G5 (Late 2005)
  • iMac G5 (Ambient Light Sensor)


You can restore the Firewire bus by resetting the SMU (System Management Unit). To learn how to reset your particular computer SMU please see:

301733: "iMac G5: How to Reset the SMU"
300341: "How to reset the SMU on a Power Mac G5 (Late 2004) or Power Mac G5 (Late 2005)"

Published Date: Oct 11, 2016