MacBook Pro Headphone Jack Problem

Open Activity Monitor, see if the 'Coreaudiod' process is active and working properly. If it is not responding (force) quit it and see if that changes anything.

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 people. Did anyone here get this fixed so that the headphone port works properly all the time?

Just wanted to share similar experience with an early 2011 macbook pro 17in running snow lion (10.7.2). the system preferences > sound prefs don't register any devices plugged into the headphone jack. the only choice showing up in the sound pref pane under "output" is "internal speakers". I took it to the apple store, and the tech simply restarted the machine and reset the pram. this worked only temporarily - the next time the headphones were unplugged and then plugged back in, they didn't work. I don't know if this indicates a hardware or a software problem, but it would be nice just to get it fixed!!

I have an early 2011 17" MBP that has had this unresponsive audio jack problem on and off for a long time--additionally it seems to be related to problems I have with the thunderbolt port:

- Sometimes I plug in headphones but only the internal speakers are seen/used.

- Most of the time when I plug a VGA or DVI adapter into the video port, the screen gets jitters or static every few seconds until I try unplugging and replugging one or more times.

- Sometimes when I plug in an HDMI adapter, one or both screens go crazy with video junk until I unplug and replug the adapter.

- Sometimes after unplugging from power, video, usb, audio, and walking around with my computer, I get kernel panics.

A while ago I had time to take it in to the Apple Store to get it looked (I tend to use it most of almost every day for work or otherwise, so not much opportunity to leave it at the shop) at but they didn't find anything immediately wrong with it and the tech had never heard of anything like the problems I was having.

I suspect that all these things have a common thread--that something is wrong with the electrical sensing capability of the ports. Maybe something is wrong with the voltage going to or from the ports? Maybe there's a circuitry defect.

The only other thing is, I had for a short while, the late 2010 version of this model and it exhibited the same video port weirdness. It also had a few unexplained kernel panics. The odds are pretty slim that I would get two different laptop editions with the same problems that no one has heard of. It IS possible but it's also possible that the cause is something inherent to me instead of the original hardware.. so I'm curious to see if anyone else has experienced all these things in the same computer.

Also the only temporary fixes I've found for the audio:

- Restart the computer

- Put to sleep, wake again.

Try setting your unix root password the same as your login password and reset your NVRAM/PRAM.

that worked for me, waking from sleep with headphones plugged in. 

Check your sound settings and at the bottom of sound setting in "general settings" make sure it says that audio jack is set for output not input.