No sound? iTunes won’t play? I first noticed that the sound icon is missing from the right side of my menu bar--mine showed a blank space where the sound icon used to be. Go to System Preferences and open SOUND. If the mute is checked, uncheck it. If it is greyed out and says that the iMac isn’t able to recognize its internal sound input or output devices, you may need to reset your system. I just fixed mine within the hour-yippee!!!
In the event the system needs to be reset--
1. First, log out and shut down system.
2. Unplug all peripherals and power cord and wait at least 15 seconds.
3. Plug in the power cord only, and turn power on.
4. Once on, plug in the keyboard & mouse. When you are back to your login screen or desktop, PREPARE to restart. WHEN THE TIME COMES, you will need to hold down the specific keys to reset in a timely manner. The keys are Control (the Apple icon), Option, and the letters “p” and “r”, and you hold down these four keys simultaneously.
5. Restart your computer and IMMEDIATELY following the startup chime, HOLD DOWN the four keys.
6. Once you hear the chime again, you may let the keys go. Hopefully, you’ll have your system’s sound restored.
Good luck!
Tina HB