My macbook this without sound. I checked the settings, and has no input or output and sound. An icon appears blocking the sound. what to do??

I am having the exact same problem and none of the very good suggestions here have helped me either. Any other ideas?

1. Open Activity Monitor (in Utilities)
2. Select "All Processes" from the drop-down list at the top
3. Click on the process called "coreaudiod"
4. Click on "Quit Process"
5. Click "Force Quit"

It will go away and come back again, and the sound should start working. No need to reboot.

Well, it works for me, anyway. Hope this helps.

OMG, you are a genius! this worked. I have been having the same problem, I tried all the other suggestions but re-formatting & taking out the battery, and voila, you saved the day. Mind my asking what exactly did I just do?

Thank you!!!

No problem at all. Glad to hear it worked for you!

"coreaudiod" is the Core Audio daemon. It deals with sound on OS X and iOS. It was clearly misbehaving and you just forced it to restart and sort itself out. This problem might recur and you may also notice it eating up your CPU time, so keep an eye on the Activity Monitor once in a while and do make a note of the fix in case you need it again.

Enjoy your sound!

Hello, I have the same problem as Luisek but it happened beause i safely rebooted the computer ( didnt know what i was doing). I tried what you just posted and it didnt work, I still have no output input devices. Help!

Sorry for my bad grammar

Hmm. I think you have a different problem from Luisek. Can you tell me if any of these sounds are working for you:

* Boot up (when you turn the box on and wait for the machine to start up)

* Emptying the trash

* iTunes

Also, when you boot up, do you get any error messages?