Macbook Pro speakers not working in OS but work in Bootcamp ?

Question

Had macbook pro for over a year so warranty is expired, i had spilled a drink on the laptop and thought that the speakers were lost for ever. But when i set up bootcamp with windows 8 the speakers now worked perfectly, this means that the speakers do still work and hopefully someone can give me some instructions on how to salvage them and get them working on OS !
Sadly i've tried resetting the Nvram (Pram) and the SMC with no change to the speakers in OS, I would like to still have the speakers functioning in OS even though they work in bootcamp and if anyones got any tips or suggestions, please help !
Frank

Answer 1

There are many possible causes for this issue. Take each of the following steps that you haven't already tried. Back up all data before making any changes.
1. Start with the steps recommended in this support article. Don't skip any of the steps. It's the starting point for further efforts to solve the problem.
2. Run Software Update and make sure you have a fully up-to-date installation of OS X.
3. If you've installed an application called "Memory Clean" or any other third-party software that is supposed to "clean" or "purge" memory automatically, remove it according to the developer's instructions and restart. You should do that even if the software is not causing the problem, because it's useless.
4. Other third-party software that has been reported to interfere with sound output includes "Boom" and "Samsung Kies." If applicable, uninstall according to the developer's instructions (not by dragging something to the Trash.)
5. If an AirPlay device is selected for sound output from iTunes (or from other applications via third-party software such as "Airfoil"), deselect it.
6. Launch the application "Audio MIDI Setup" by entering the first few letters of its name in a Spotlight search and selecting it in the results (it should be at the top.) Select Built-in Output from the list on the left. If the Mute boxes are checked, uncheck them.
7. If a red light is coming from the audio-out port, the internal switch is stuck in the position for digital output. You may be able to free it by inserting and removing a mini-stereo jack of the proper size. Inserting any kind of tool in the port may cause damage that won't be covered by your warranty.
If there's no red light, the switch may still be stuck in the headphone position. Try to free it the same way.
8. Disconnect all wired peripherals except keyboard and mouse, if applicable. If more than one display is connected, disconnect all extra ones. Restart and test.
9. If you have a MacBook Air, turn off Bluetooth and restart.
10. Start up in safe mode. Don't log in; just restart as usual when the login screen appears. When you do, make sure the words "Safe Boot" do not appear in the login screen. If they do, the system is still in safe mode and sound won't work.
11. Reset the NVRAM.
12. Reset the SMC.
13. Triple-click anywhere in the line below on this page to select it:
/Library/Preferences/Audio
Right-click or control-click the highlighted line and select
          Services ▹ Reveal in Finder (or just Reveal)
from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator login password. Restart the computer and empty the Trash. Recreate your settings in theSound preference pane.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination  command-C. In the Finder, select
          Go ▹ Go to Folder...
from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.
14. Reinstall OS X after backing up all data.
15. Make a "Genius" appointment at an Apple Store.