I know this is an old thread but, this exact same thing is happening with my 17 inch early 2011 Macbook Pro. If I restart my computer and then plug in my headphones the computer will recognize them but, it will stop working at some point and no headphones I use will be recognized until I reboot. I've opened one ticket with Apple about this already and have been told to take the machine in for repair. On a two week old laptop? This seems to be some ongoing issue for a few...