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Does resetting your MacBook's PMU solve the Mooing problem? (MacBook users only)

  • Yes.

    Votes: 18 11.8%
  • No.

    Votes: 46 30.1%
  • My MacBook does not have the Moo.

    Votes: 89 58.2%

  • Total voters
    153

MacRumors

macrumors bot
Original poster
Apr 12, 2001
55,001
17,378


MacRumors user "netdog" reports that he has successfully been able to get rid of his MacBook's "moo" issue by resetting his Power Management Unit (PMU). The steps he took were:

1. Shutdown and disconnect power.
2. Remove battery.
3. Hold down power button for more than 5 seconds.
4. Reinsert battery and reconnect power.
5. Boot.

Detailed information on resetting the PMU on MacBook and MacBook Pros is available via Apple's Support site. Resetting the PMU should only be considered in last-case scenarios, and should not be done more than once every 48 hours.

Disclaimer: Users should proceed at their own risk, as MacRumors cannot be held liable for damages that may be caused by following the instructions listed above. MacRumors has not independently tested the above procedure as such resources are unavailable, but the tip is rather offered as a courtesy. Users are strongly encouraged to contact their AppleCare support representative and consult Apple's documentation for guidance if following the aforementioned steps.

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macaddict06

macrumors regular
Well, I'm glad someone found a fix, but shouldn't Apple's quality control unit be all over this? It seems like they have taken a very light approach to the new machines since they came out in January and May...makes me think about getting a PBG4 instead of a MBP revB...we'll see what becomes of this.
 

netdog

macrumors 603
Feb 6, 2006
5,759
37
London
This information came from Apple online support, just so everyone knows. I am confident that it won't harm anyone's system, and is obviously an Apple feature that they don't document for us. After 3.5 hours, I have heard two Moos. When I called them, it was mooing incessantly, much like in the recent video...on/off/on/off. It was just awful.
 

lars steenhoff

macrumors newbie
Feb 23, 2006
21
0
Yes, this is also what apple instructed me to do over the phone.
It seems to lessen but not completly remove the noise from the cpu.
The software quiet mbp completly removes the noise, at the cost of heat and battery life.

hope the next generation of intel chip will be more quiet.
 

netdog

macrumors 603
Feb 6, 2006
5,759
37
London
lars steenhoff said:
Yes, this is also what apple instructed me to do over the phone.
It seems to lessen but not completly remove the noise from the cpu.
The software quiet mbp completly removes the noise, at the cost of heat and battery life.

hope the next generation of intel chip will be more quiet.

Now that I have experienced this for myself, I am sure that it was the fan going on and off, and not the chip. My guess is a firmware update will really nail this problem, and I wouldn't be surprised to see one soon.

What was really curious for me is that I had a silent MB bought in the first week of its release. It was only with 10.4.7 that it started to moo, and was doing so like mad. Like I said, I have been pushing the processor quite hard, and have only heard the fan whir twice, which while not as good as it once was, is a HUGE improvement over how it was before I did what Apple suggested.

I am really curious to see if this helps people who had the moo prior to 10.4.7

All that I can say for sure is that it has really helped me.
 

nagromme

macrumors G5
May 2, 2002
12,546
1,196
"Mooooo?"

I haven't heard the "moo" (no Intel Mac for me yet), but that sounds kind of cool :)

How can I enable the Moo feature if I get a Mac that doesn't have it by default?
 

Roads0

macrumors newbie
Dec 21, 2005
25
0
Standing on the Moon
I just got my Macbook on Monday and I have no Moo. Actually, I've noticed thta the fan doesn't even come on when it gets really hot. Maybe Apple has fixed the problem with the Macbooks shipping now?
 

netdog

macrumors 603
Feb 6, 2006
5,759
37
London
Roads0 said:
I just got my Macbook on Monday and I have no Moo. Actually, I've noticed thta the fan doesn't even come on when it gets really hot. Maybe Apple has fixed the problem with the Macbooks shipping now?

Mine was bought two days after the MB was first released, and it was dead-silent until 10.4.7
 

QCassidy352

macrumors G4
Mar 20, 2003
11,782
5,431
Bay Area
lars steenhoff said:
Yes, this is also what apple instructed me to do over the phone.
It seems to lessen but not completly remove the noise from the cpu.
The software quiet mbp completly removes the noise, at the cost of heat and battery life.

hope the next generation of intel chip will be more quiet.

If Quiet MBP removes the noise, then you're talking about the "whine," not the "moo." This is a proposed fix for the "moo." Both are problematic for some (i.e. me). :)
 

jbouklas

macrumors regular
Mar 2, 2002
124
0
NY
Funny, my MacBook always mooed, and the power adapter whined. As of two weeks ago, my power adapter AND MacBook both whine, and it still moos. The 10.4.7 update did nothing for either of them. Then, I tried to reset the PMU just now- still no help. I have AppleCare, so once I know that they fix the problem, I'll call them about it. I'm already on my second MB- returned my first a week or two after I bought it for an exchange, same problems. So, I'll wait it out.

-Jim
 

Stella

macrumors G3
Apr 21, 2003
8,745
5,999
Canada
lol - MMMMMOOOOOOOOOOO!!11oneone

Wonder if these MacBooks can catch Mad Cow disease too ( BSE ) :)
 

artifex

macrumors 6502
Nov 1, 2003
336
0
Stella said:
lol - MMMMMOOOOOOOOOOO!!11oneone

Wonder if these MacBooks can catch Mad Cow disease too ( BSE ) :)


I think maybe they used the same vendor for the motherboards (sorry, y'all call them logic boards) as Gateway :)

Macworld's latest issue seems to claim none of these problems are a big deal.
Of course, they also are just now reviewing the MB. Yet another reason for me not to renew my subscription...
 

solvs

macrumors 603
Jun 25, 2002
5,684
1
LaLaLand, CA
I've heard of this mooing thing, but never actually heard the actual mooing itself. Is it like one of those toys where you pull the thing and it moos when it lands on the cow? Or like one of those baby or dog toys that lets out a mooing noise when you squeeze it?

Now I'm curious.
 

QCassidy352

macrumors G4
Mar 20, 2003
11,782
5,431
Bay Area
No, it did not work for me. Thanks for the try tho, netdog.

On the plus side, my macbook does not heat up to the requisite temperature (about 68 C core temp) very easily at all with 10.4.7, so it's really not much of a problem anyway. Running photobooth used to heat it up that much, but no longer does.

edit: actually... it seems worse now. Not louder, but as I said, after 10.4.7, the moo didn't start until about 68 C. Now, after resetting the PMU, the moo starts at about 65 C, and that makes a big real-world difference in terms of how often I hear it. :(
 

D3LM3L

macrumors regular
Mar 31, 2005
122
0
Detroit
I do feel bad for everyone with a mooing MacBook, but I just broke out in laughter when I heard a clip of it! Anyone else do the same thing when they first heard the sound?
 

it5five

macrumors 65816
May 31, 2006
1,219
1
New York
I'm not that bothered by the moo. I'll just wait until a firmware update or something I guess.

When I first heard it I was really surprised at how lifelike a moo it is.
 

solvs

macrumors 603
Jun 25, 2002
5,684
1
LaLaLand, CA
D3LM3L said:
I do feel bad for everyone with a mooing MacBook, but I just broke out in laughter when I heard a clip of it! Anyone else do the same thing when they first heard the sound?
Where'd you hear it?
 

4screen

macrumors newbie
Jun 11, 2006
4
0
nagromme said:
"Mooooo?"

I haven't heard the "moo" (no Intel Mac for me yet), but that sounds kind of cool :)

How can I enable the Moo feature if I get a Mac that doesn't have it by default?

My wife suggests you try and milk it. :)
 

QCassidy352

macrumors G4
Mar 20, 2003
11,782
5,431
Bay Area
ugh, I really wish I'd just left well enough alone. My macbook seems to reach 65 C quite easily, but 68 C not nearly so easily. Meaning now I'm hearing the "moo" just doing regular tasks whereas I did not. (I put moo in quotations because mine really doesn't sound like a moo... just like fans ramping up and down over and over. Which is just about as bad, IMO.)

So let me warn you all, try this PMU reset at your own risk. :(
 
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