Every so often (probably every 4th or 5th time I start my computer), I do not get any sound from my MacBook Pro. If I press the volume buttons, I see the "No" symbol indicating the sound is off. However, pressing the mute button does not reactivate it. Restarting my computer normally resolves the problem, but it is frustrating.
MacBook Pro, OS X Mountain Lion (10.8.2)
Remove the headphone.
If you see red light in the headphone port, plug the headphone
in and out of the port 5 or 6 times to flip the microswitch inside.
Sound output may be stuck in the digital mode.
Reset PRAM. http://support.apple.com/kb/PH4405
Reset SMC. http://support.apple.com/kb/HT3964
Choose the method for:
"Resetting SMC on portables with a battery you should not remove on your own".
Best.
I took the laptop to the Apple Store. The sound did not work, even with headphones, and the technician checked the headphone jack with a flashlight and saw nothing of concern. I had reset the PRAM once but the problem continued. They are reviewing the hardware/software (thank goodness for Apple Care).
My computer intermittently does not play sound
