Maybe something here:
The 1st one may apply,about previous OS.
Tried everything else, maybe you might find something here?
Just trying to help, as non of the "regular fixes" have been sucuessful.
Best of luck.
Post if you find an answer
I had the same problem with 10.8.2, which just started this morning, on a 2008 MBP. The sleep fix did not initially work, but after sleeping and waking a few times, then restarting, the internal speakers are working again. The only recent upgrade, last week I believe, was a recommended Safari update from the App Store. It seems unlikely that had anything to do with the problem, because I don't use Safari very often, and not at all since the update.
Had same issue but sort of found a fix and something interesting.
My MBP is the last model of the 17"
My internal audio was sort off and on. volume up and down button work work sometimes.
After reading this i checked the little headphone port and there is a bright light inside flickering.
Must be some sort of sensor.
Anyways, I blasted the heck out of the hole with a can of duster air and boom - fixed.
Im pretty sure it's not software releated because my problem was very off and on adn didnt happen for quite a while after 10.8.2. I'm just guessing it's a sensor.
i also should note that when it was happening it must have been flickering on and off and slowing things down because my mbp was "hanging" alot until i fixed it too.
I spilled some tea on my laptop. After leaving it off for a short period I turned it back on and although I could hear sounds up until I logged into an account. Once I was logged in (on any account) my internal speakers weren't recognized (everything was greyed out)
I thought I killed them with the liquid but they worked booting and at the login screen. I reset the SMC and NVRAM and despite apple not listing anything speaker related as something those two items are responsible for, they're working now. Just wanted to add that in case anyone having a similar problem reads this.
In my case:
- normal startup chime
- no sound from internal speakers, taskbar icon grayed out
- Internal speakers disappeared from the list in System prefs -> Sound -> Output
- normal sound through headphones
- noticed the red light from inside the headphone jack, but it quickly turned off and stayed off
What did NOT work:
- multiple sleep/wake cycles
- multiple reboot cycles
- PRAM reset
- SMC reset
- plugging in and out the headphones multiple times
What did work:
- remembering that someone reported fixing the problem with a toothpick, I repeated the in/out plugging of the headphones while applying a little bit of gentle wiggling inside. I noticed that the sound icon would stay black for a moment longer each time I pulled the plug, and then it just stayed on and the sound now works again.
It seems to me that this behavior has nothing to do with the OS, and that reports of the problem occurring after an update are probably a coincidence. A faulty small switch is a more likely cause.