Hi, the computer starts with sound, but when it's ready to use the volume icon become gray and i cannot turn down or up the volume.
the headphone also doesn't work; the Sound in system preference says "no output device found".
i google it and try to reset the SMC, the problem still exists, pls help me how i can fix it!!!
THX!
There are many possible causes for this issue. Take each of the following steps that you haven't already tried.
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. If you've installed a software equalizer called "Boom" or anything similar, update or delete it and restart.
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. Reinstall OS X after backing up all data.
14. Make a "Genius" appointment at an Apple Store.
There are many possible causes for this issue. Take each of the following steps that you haven't already tried.
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. If you've installed a software equalizer called "Boom" or anything similar, update or delete it and restart.
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. Reinstall OS X after backing up all data.
14. Make a "Genius" appointment at an Apple Store.
Hi,
I experienced this exact same problem too. It happened after I did the Mavericks Update 10.9.4. The Mac could not see the audio devices in System Preferences, however it was still visible in the System Report. The AppleTV and bluetooth speakers are still functional, just not the internal ones.
I was able to temporarily fix it through Terminal.
If you run "sudo kextunload /System/Library/Extensions/AppleHDA.kext" and then run "sudo kextload /System/Library/Extensions/AppleHDA.kext" it seems to bring back all the audio functionality again. But when I reboot the MacBook (I have 15" Retina (Late 2013) full spec), the audio devices disappear again.
I eventually reinstalled OSX and restored from a TimeMachine backup and it has now been fixed completely.
Hope this helps.
I have a 2014 Macbook Pro retina and I too have this problem. Nothing has worked to solve the problem and I know that I am now facing a reinstall. So..basically, this means that if you "unplug your headphones at an inconvenient time" you may need to reinstall your operating system. Sounds excellent..a high quality design.
No sound on Macbook pro retina.
