Symptom
The mouse pointer and keyboard may become unresponsive when used with the USB Keyboard Extender Cable. The computer operates normally without the extender cable.
Solution
Verify the symptom by removing the extender cable. If your computer operates normally with the extender cable removed, bring the cable to an Apple Authorized Service Provider to exchange it according to the terms of the Limited One-Year Hardware Warranty.
Removing the extender cable from the USB device returns the computer to normal operation if a replacement cable is not immediately available.