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Mike, Mac Medic
Category: Mac
Satisfied Customers: 8997
Experience:  Over 20 years IT experience with Apple computers in publishing, marketing and design.
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I have apple computer and all of a sudden my sound seems locked

Customer Question

I have apple computer and all of a sudden my sound seems locked in mute. I move the volume up but goes right back down to mute. Mute logo is showing on my screen. I have not done any changes or recent upgrades. Your assistance pls. My specs are:

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.8 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache: 4 MB
Memory: 2 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version (system): 1.21f4
Serial Number (system): W87431DGZCV
Hardware UUID: 00000000-0000-1000-8000-001B63ACD48E
Submitted: 4 years ago.
Category: Mac
Expert:  Jesse replied 4 years ago.

Jesse :

Hello, and welcome to!

My name is Jesse, and I'm here to help.

Jesse :

Try plugging in and unplugging a pair of headphones several times.

Customer :

That makes no difference. I push up volume button and comes right back to mute. If i totally restart it will work for a few minutes then goes back to mute.

Customer :

Doesnt work.

Jesse :

Try resetting the PRAM, by holding the P+R+Option+Command keys together while restarting. Hold the keys for 1 full restart.

Customer :

Does not hold lastt about 30 seconds then returns to mute

Jesse :

Okay, if you open System Preferences (located under the Apple menu in the upper left corner of your screen), and select the Sound pane, is the box for Mute at the bottom of the screen unchecked?

Customer :

Cant uncheck it. The sound will stay for about 5 min then automatically goes off.

Jesse :

Okay, but that box is checked, that's good to know.

Jesse :

Let's try this:

1. Open a new Finder window (click the smiley face icon on the far left side of the Dock).
2. From the Go menu at the top of the screen, select Macintosh HD.
3. In the Library folder, go to the Preferences->Audio folder, and move the file to your Desktop.

Jesse :

Make sure that System Preferences is closed when you do this, then reopen it and see if it works.

Customer :

Still the same no change

Expert:  Mike replied 4 years ago.
Try this:

Resetting the SMC & PRAM for Mac Pro, Intel-based iMac, Intel-based Mac mini, or Intel-based Xserve
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Wait fifteen seconds.
4. Attach the computer's power cord.
5. Wait five seconds, then press the power button to turn on the computer.
6. Press and hold the Command-Option-P-R keys before the gray screen appears.
7. Hold the keys down until the computer restarts.
8. Release the keys. 

Let me know
Customer: replied 4 years ago.

NO tried several times. It will work for about one minute then like clockwork it goes off

Expert:  Mike replied 4 years ago.
So no alert sounds even? Is there any particular app you are using when it stops?
Customer: replied 4 years ago.

NO sound when it starts up. I can use keyboard volume F key and will work but still goes off in about a minute or so. Doesnt matter about app.

Expert:  Mike replied 4 years ago.
What system version please?
Customer: replied 4 years ago.

OSX 10.8.2 I just reloaded it today. No change. It is almost like it is on a timer.

Expert:  Mike replied 4 years ago.
I want you to check some things that may or may not be affecting the situation. I am required to post any procedure as an Answer even if it is just a diagnostic test, so please ignore the Rate to Finish box and Reply to Expert after you have tried that.

Restart the computer while holding the Command and R keys to boot to Recovery HD partition, when it boots select the Disk Utility and Continue. Then select Macintosh HD on the left and first Verify Disk on the right and if that is OK Repair Permissions. If Verify Disk is not OK try to Repair Disk.
Expert:  Mike replied 4 years ago.
Did you try that?
Customer: replied 4 years ago.

Yes i have done that as well and still same.

Customer: replied 4 years ago.

Nothing is changed

Expert:  Mike replied 4 years ago.
Put headphones in and out a few times, the switch that turns that on and off might be stuck. Wiggle it a little and pull it in and out. :Let me know
Customer: replied 4 years ago.
Still same problem
Expert:  Mike replied 4 years ago.
Go to System Preferences / Security & Privacy / General click on Advanced, is Disable remote control infrared receiver checked?
Customer: replied 4 years ago.

No it is not checked

Expert:  Mike replied 4 years ago.
Check that then also go to System Preferences / Users & Groups / Select your account then go to Login Items, tell me what is listed there