I needed a 3.5 audio cable extender to use on my mac. I notice that if I have it and my headphones with microphone plugged into the MacBook Pro on bootup, it all works just fine. If I unplug my headphones from the extender cable, leaving the extender plugged into the MacBook - or if I unplug both from the MacBook, and then replug in my headphones, the MacBook no longer recognizes the microphone. I've tried doing 'sudo killall coreaudiod' but this does not help. The only solution I have found is to reboot the laptop. Suggestions on a better way to fix this?