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Sound disabled upon restarting on 21.5" running 10.7.3

M

M3G4

macrumors regular
Original poster
May 4, 2007
100
0
Kent, UK
Hi all,

I was wondering if anyone knows of a fix for my iMac 21.5" which seems to disable the onboard sound upon restarting?

I understand that this can be remedied by resetting the SMC but I cannot be expected to do this each and every time the machine is restarted. Is there any way I can get it to work permanently?

Upon restarting the volume icon is greyed out, and pressing the volume up/down keys bring up the volume box with a "no entry" sign underneath the icon. I've tried unplugging and replugging the external speakers to no avail, and this occurs with the internal speakers also. I've checked the correct device is selected in the volume settings and the optical output is not switched on.

Lion really is a sack of ****, isn't it?
 
Are you saying that you've tried resetting the SMC and then it works fine until you reboot? If so, I can't personally think of a reason as to why that would be happening. Typically an SMC reset would fix it "permanently" (within reason - definitely not just until you reboot again).
 
Either way - is this a problem with my machine or the OS? It only started happening after installing 10.7.3.

Pretty sure resetting the SMC (unplugging, holding for 10 secs, plugging back in etc) was what fixed it before.
 
From the Apple site:

Resetting the SMC:

Shut down the computer.
Unplug the computer's power cord.
Wait fifteen seconds.
Attach the computer's power cord.
Wait five seconds, then press the power button to turn on the computer.


Apple states on their site that the SMC is associated with problems relating to, but not restricted to:

Fans
Lights
Power
System Performance
Video

So, from looking at that, it seems that the SMC shouldn't really be affecting your sound.

However, as GGJstudios pointed out, the NVRAM is definitely sound-related,.

Have you tried resetting the NVRAM/PRAM to see if that fixes the problem?

Given that you said that the problem can be fixed and that it only started occurring after you updated to 10.7.3, I'm assuming it's an OS problem.
 
M3G4 said:
Either way - is this a problem with my machine or the OS? It only started happening after installing 10.7.3.

Pretty sure resetting the SMC (unplugging, holding for 10 secs, plugging back in etc) was what fixed it before.
Click to expand...
The SMC doesn't relate to volume or speaker issues.

Intel-based Macs: Resetting the System Management Controller (SMC)
Fans
The computer's fans run at high speed although the computer is not experiencing heavy usage and is properly ventilated.

Lights
The keyboard backlight appears to behave incorrectly (on Mac computers that have this feature).
The Status Indicator Light (SIL) appears to behave incorrectly (on Mac computers that have an SIL).
Battery indicator lights, if present, appear to behave incorrectly (on portables that use non-removable batteries).
The display backlight doesn't respond correctly to ambient light changes on Mac computers that have this feature.

Power
The computer doesn't respond to the power button when pressed.
A portable Mac doesn't appear to respond properly when you close or open the lid.
The computer sleeps or shuts down unexpectedly.
The battery does not appear to be charging properly.
The MagSafe power adaptor LED doesn't appear to indicate the correct activity.

System Performance
The computer is running unusually slowly although it is not experiencing abnormally high CPU utilization.

Video
A computer that supports target display mode does not switch into or out of target display mode as expected.
A computer that supports target display mode switches into or out of target display mode at unexpected times.
Click to expand...
Mac OS X: What's stored in PRAM
Some information stored in PRAM includes:
  • Display and video settings such as refresh rate, screen resolution, number of colors
  • Startup volume choice
  • Speaker volume
  • Recent kernel panic information, if any
  • DVD region setting
Click to expand...
 
Right, I just zapped the PRAM. Nothing - sound still out. Restarted, still no sound.

Reset the SMC, the sound returned.
 
TheAppleSource said:
Hmmm, strange.

To be honest, I'm not entirely sure what's going on then.

Have you tried restarting without the external speakers plugged in?
Click to expand...

Yeah, no luck unfortunately. Also tried replugging them whilst the system is on - still no luck =(
 
Try what this guy suggests. Although I'm not sure if that's going to be the same for an iMac.

Or try using the attached fix that someone on MacRumors has posted before (sorry, can't remember who it is).
 

Attachments

  • AudioFix.zip
    22.9 KB · Views: 218
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