9 Replies Latest reply: Jul 10, 2012 2:57 AM by spc0114
fligtar Level 1 Level 1 (0 points)
About once every 2 days for the past 2 weeks my iMac will freeze and emit a very loud electronic sound that is changing (not the same noise the whole time). It seems to always happen when I'm playing music in iTunes or a QuickTime video, though it's not something that can easily be reproduced (I'll have listened to music for hours before it happens).

If my headphones are in the sound goes through them, but if not it goes through my external speakers and it's extremely loud. The computer freezes and I can't do anything except hard restart to stop the noise.

Any ideas? Thanks!

iMac 27" late 2010, Mac OS X (10.6.6)
  • William Boyd, Jr. Level 6 Level 6 (10,515 points)
    fligtar wrote:
    About once every 2 days for the past 2 weeks my iMac will freeze and emit a very loud electronic sound that is changing (not the same noise the whole time).


    Welcome to Apple's discussion groups.

    If you launch the Console utility and look for messages around the time of the freeze, what do you find?
  • fligtar Level 1 Level 1 (0 points)
    Thanks for replying. The time it happened after your response I looked in all of the Console logs and couldn't find anything around the time of the freeze. I decided to wait until it happened again to be sure.

    It happened about 10 minutes ago, so after restarting I immediately went to Console and looked again, and there's nothing within several minutes of the freeze.

    The only thing I was doing on my computer was listening to music; I wasn't typing or actively doing anything else.
  • William Boyd, Jr. Level 6 Level 6 (10,515 points)
    fligtar wrote:
    The time it happened after your response I looked in all of the Console logs


    The best log choice for that is probably "All Messages".

    and couldn't find anything around the time of the freeze.


    That suggests that it's not a software problem, which may point to hardware. You could run the diagnostics that came on the system disc(s) with your Mac, but if it's an intermittent problem it could be hard to track down.
  • Anti-Fanboy Level 1 Level 1 (45 points)
    Try starting in safe mode : http://support.apple.com/kb/ht1455


    Go to about this mac, and look for your audio entry. Most likely the kernel extension is haggard. If it doesn't say anything - then installing a new kext will fix it. If you don't feel comfortable installing a new kext, then backup and reload the PC. Snow Leopard isn't infalible, so it sounds like something is corrupted.

    Repairing permissions seems to fix a lot of things - so you can try that too. Boot from the OS disc and repair your drive. If that doesn't work, take the more extreme measures of the backup and reload.
  • spc0114 Level 1 Level 1 (0 points)

    i have exactly the same problem, did you fixed it?

     

    For me, it happens once or twice a week (very annoying, and the noise was so scary to drive me crazy). I just thought about to check my system log and found lots of audio device failure happens during the time (log messages are sent from iTunes).

     

    Have tried cleaning the PRAM, system check tool (from the apple care disk), disk utility from the Applications folder and seems not working.

     

    mid 2011 iMac 27" with lion (10.7.4), 16GB Ram.

  • RRFS Level 5 Level 5 (4,490 points)

    Install iStat Pro and look at your tempratures after a long session. My guess is a heat related issue.

     

     

    http://islayer.com/apps/istatpro/

     


  • spc0114 Level 1 Level 1 (0 points)

    sorry for the delay.

     

    after that day my iMac crashed two times, and it seems that iTunes is not the reason of the crash. cause when it is "about to crash", my iMac just acts wierd. like DTerm (another cool app from app store) cannot work correctly. or some program (safari, finder, even, gcc seems to be unstable at the time) runs laggy than usual.

     

    I think I might just figured out the reason, it possibly be third party software issue. I was using an app called "pps" which could be downloaded from app store.

     

    anyway, after i removed the app, everything seems perfect!

    and it is not tempurature issue... i think. cause that happenes randomly.

     

    hope this comment does help to someone

  • spc0114 Level 1 Level 1 (0 points)

    well, it did not take effect at all. The problem still occurs, and I finally did a clean install (cmd+opt+R when boot up).

     

    The problem seems not exists anymore and don't know why that my iMac just crashes more frequently. The recovery partition seems broken because every time I try to boot from recovery partition it tells me my installation is failed and have to restart.

  • spc0114 Level 1 Level 1 (0 points)

    I finally figured out the reason: BAD RAM.

     

    before that, I have downloaded the apple hardware test tool and ran memory test over night. download memtest tool and did a fully test. ALL PASSED so I did not even think about it.

     

     

    Thanks for all the replys and I just learned alot tricks about cleaning and examining my mac. Thanks again!