When I use my headphones the sound is perfectly fine and everything but when I take them out, even with volume all the way up I cannot hear any sound at all and I don't like it.
MacBook Pro (13-inch Mid 2012), OS X Yosemite (10.10)
1.Plug in and 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.
2. Reset PRAM. http://support.apple.com/kb/PH14222
3. 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.
Sound with headphones but no sound without them
