I'm having some strange issues on my MBP Retina running OS X 10.8.2.

The audio balance changes, and the right speaker is almost muted.

Anyone know what could be wrong here?

  • Could you verify that this i not caused by a broken jack cable? Try replacing the cable between your mac and your speakers. If it's broken and you move, it might lose the signal of one channel. Jan 19, 2013 at 21:47
  • Yeah, sure, I've already checked this. I've tried with earphones/speakers and mac own speakers, so when I check the balance on the system preferences > Audio and the balance bar shows it has been changed to left... oddly enough
    – Manu
    Jan 20, 2013 at 3:06
  • Do you use Skype or some other VOIP program? While in a call, these usually only play audio from one speaker to avoid interference with the microphone. Perhaps it's related to this.
    – Szabolcs
    Jan 21, 2013 at 0:07
  • Nope, I've checked that too, and I don't even have Skype installed on my machine...
    – Manu
    Jan 22, 2013 at 15:07
  • 3
    I'm having the exact same issue with my MBP Mid-2010 "13. I noticed it a few days ago whenever I plugged in my speakers or headphones, and I thought it was a headphone issue until I decided to check the sound balance, and it was almost completely to the left. It's happened several times, and it seems as if it does it every time something is plugged into the headphone jack. It has to be some weird bug that Apple has yet to issue a patch for!
    – user50776
    Jun 7, 2013 at 3:23

4 Answers 4


I've had this problem on multiple MacBooks (from my old Powerbook 15 from 2003 to prior to finding this question on my late 2011 MBP 13").

Apple has acknowledged it as a bug when pressing the volume buttons during heavy CPU usage way back in OS 10.2! The solution was to go back to preferences and set it back where you wanted.

  • 5
    Thanks for this. Apparently is still happening on MacOS Sierra, as I had to re-center the balance for the millionth time :) May 1, 2017 at 20:41
  • 6
    Hello from 2018! The bug still happens in High Sierra.
    – JVon
    Aug 5, 2018 at 2:34
  • 4
    Greetings from late 2019. It's still there in Mojave.
    – JeffE
    Dec 8, 2019 at 20:29
  • 10
    March 2020 called to say that it's still not fixed Mar 28, 2020 at 8:35
  • 6
    Still here as of Catalina 10.15.6... I'd say shockingly but that'd be a lie. Aug 6, 2020 at 20:36

There is an open source MacOS app that attempts to work around this acknowledged bug. The app watches for balance changes and centres immediately.

Disclaimer: I made the application.

  • 2
    Thanks for posting and self disclosing. Best of luck with the app.
    – bmike
    Aug 20, 2018 at 2:55

I have this exact same issue. mid-'12 rMBP 15'' 256/2.6/16GB. OS X 10.8.2

First noticed the sound issue with my ear monitors (Shure headphones) plugged into the computer: the sound in my R earbud was like 80% diminished. But the earbuds worked fine on my iPhone 5, perfect output in each side. Last night, while watching a Netflix movie (occasionally plugging in my earphones into the rMBP), the laptop's R speaker suddenly lost all output. I freaked out, obviously, but quickly discovered that the balance bar had been shifted 90% to the L. Funny how that just changed itself mid-movie watching. Also, after I fixed the slider bar and the laptop's speakers started functioning as normal, when I plugged my earbuds back in, I had to go BACK into Audio preferences again to change the balance bar. Strangely enough, it was shifted L again, but more like 50%, not as extreme as it was for the laptop's speakers themselves.

Absolutely a software bug.


This (or something else that has the same effect) is still happening on 10.15.7 (19H2), nearly 8 years later

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