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  • BrothaJay Level 1 Level 1

    I have heard there is a shut-down sensor in the MBP or MBA' for when they overheat - I've never seen it happen, nor am I aware Apple has EVER posted the temp value when this is supposed to occur. One thing I know is that the early MBA's KT hits peak just to control the fans (I'm at 100% CPU, CPU temp is 50c and fan at 2500 - utter joke) or if Flash is recognized (not necessrily running). The heatsink in an MBA may be same/similar to the MBP (I don't have an MBP to check) but it consists of a small sheet of thicknened aluminum/tin foil connected to one tiny (somewhat useless) fan that does get dirty and needs cleaning. The crazy part is that the foil is about 1mm or more above the die (cpu/gpu) - it does not come in contact whatsoever and a huge dollup of thermal paste is required to span the's basically useless. And NO, the aluminum top case is not used to disperse heat, with the exception (maybe) for the power inverter. A test with the MBA to show heat-related KT (or useabliity of Flash) use a fan against the back of the display - it will increase KT issues.  What is needed is to 'extract' hot air, not obstruct it by blowing against vents (in rear of MBA) or bottom case. What seems to work well is a 'vacuuming' of hot air from the back - or simple unobstruction of 'clean' vents/fan. Not much else you can do except under-clock the CPU which I've heard Apple restricted in newer devices. [sorry to hijack]

  • IEBA1 Level 1 Level 1

    More developments...
    I was having issues where my MBP would start to run slow, but now the KT is NOT taking over the machine. I'd try rebooting to start everything fresh and the machine would not. start. up.

    It was very hot, and no amount of twiddling or p-ram resets would get be back into a machine that was running 5 seconds ago.


    I put a fan on it to cool it down. I did nothing else.

    2 hours later, it starts up fine.


    I thought maybe it was bad RAM so I removed one stick, and then the other, this made no difference.


    I left the fan on the side of the computer blowing across the top and bottom (I had the back edge of the laptop lifted up on a wrist wrest) and I left the battery out and the RAM door open. (Maybe the RAM was getting hot?) and while the fan was going, I never had a problem rebooting the machine.


    Take the fan away and it was repeatable. If the computer was hot, it would not get past the initial grey screen. Ever. But if I turn it off and do NOTHING but let it cool down. In a couple hours, it runs perfectly fine.


    So I bought a "laptop cooler" to blow on the bottom of the machine (battery in and RAM door closed) and it's been pretty reliable. The cooler I got has a big 160mm fan that runs quietly, but there's no option to crank up the speed if I need more cooling.


    So its not the RAM. It's all about something on the motherboard going wonky when it gets hot.

  • kallisti Level 1 Level 1

    clean the dust out of your **** computer

  • IEBA1 Level 1 Level 1

    I replaced my HDD with SSD and there was zero dust in there.

  • BrothaJay Level 1 Level 1

    Reply to IEBA1:


    Sorry to hear this. You DID check iStat to see that the fan was actually working? Did you 'update' anyting - or maybe an app updated automatically to something that doesn't play nice...? From your other posts it does sound like you have a hardware problem, as your symptoms are not like the typical KT maxing out or Kernel Panic due to overheating.


    Did you notice if Spotlight was indexing? That can go on for days/weeks and keep the KT up. It can also make your machine grind to a halt... I realize you assumed it wouldn't be working because of 'no changes' to your external drives....but I'd check nonetheless, especially after replacing the primary drive (to SSD) recently.


    Time Machine?


    But with all due respect, per your posts, you are running that machine like a thoroughbred! It's a 2006 MBP running 10.5 (Leopard) - not exactly its former self... maybe it's time to change the thermal paste, or consider upgrading.


    FCE will certainly heat it up as will transfer of very large video files between all the peripherals you're using. I'm not saying this is your case, just noting all the things you're using your MBP for:


    24" Dell 1920x1200

    Dropbox, and Xmarks


    SMC Fan Control



    Try thermal paste; ensure 'both' fans are working; check movers/grill ahead of fans -not just fans (blow through pipe); upgrade to Snow Leopard? Upgrade the machine.


    Hope you figure things out!

  • tingotanca Level 1 Level 1

    Hello to all,


    Some months ago, I posted the solution that was working for me: vacuum-cleaning the fans of my MacBook Pro. I believed that this resulted in breaking the vicious circle of overheating and kernel_task running amok. I was repeating this procedure each time the computer seemed to slow down, every couple of months or so. Last time, however, a bit over a month ago, the effect lasted only very shortly. But while the kernel_task still was putting an exagerate load on the CPU, two and only two specific applications–always running on this machine–were taking their toll: Firefox (up to 150% CPU usage, regardless of version) and iTunes (constantly varying between 50 and 110% or so). I have posted elsewhere how I had also managed to reduce iTunes' CPU usage by tackling its (unrequested) desires to access the iTunes Store, but this didn't seem to have an effect any longer.


    I was therefore going to look into the workarounds posted here lately, in particular the detailed one offered by However, the machine had to be sent in for repair before that, as something rather curious had happened.


    I basically never use this MBP's battery: it's always on its desk, plugged in to the Cinema Display's power supply. This is probably the reason I didn't notice anything wrong until the battery was drained within a few minutes during a power failure. I then found this warning in the Energy Saver pref. panel: "Service battery. Estimated time until full: ", where I can't remember the value I saw after "full:" the first time I looked. But within a few days it had turned into this: "Estimated time until full: (null) 0%". Simultaneously, the values returned by SystemProfiler for the battery were looking pretty erratic compared to another, well-functioning MacBook Pro I have here. Moreover: by the time I'd got things sorted out to drop the MBP at the Apple retailer who then would forward it under Applecare to Apple's regional workshop (the whole procedure took over a week), the battery wasn't showing anywhere anymore, in any application or utility. The person at the Apple retailer said he'd never seen such a thing in his years selling and servicing Macs.


    Why all this on this thread right now? The battery was duly replaced. When I did ask them later, I was informed that the only thing performed by the tech together with the battery replacement had been a ritual SMC reset, which I believe I also did when I was originally trying to get to terms with the slowdowns. But the main point is that since getting the MBP back–that was two weeks ago–the slowdowns are completely gone and the activity monitor is showing absolutely reasonable one-digit CPU uses, with an occasional, very brief peak up to 30-40% if, for example, Firefox is loading a Flash video.


    I'm not competent to determine the exact interactions between the battery turning bad, the kernel_task or other applications running wild, the computer overheating, and even the SMC reset. Which of these causes the others is beyond my understanding. But at this point I'd strongly suggest to anyone with this particular issue to take a look at the condition of their battery.

  • BrothaJay Level 1 Level 1

    I have a question for you MBP'ers out there regarding what Tingotanca says. I'm on my second MBA (Early 2008) battery - the first one swelled to epic proportins on less than 100 cycles. This one is on 730 cycles and condition "Normal". I still get 3-4 hours out of it.


    But do you guys get this problem?

    If the charger is plugged in I DO get excessive heat (expected) sometimes an erratic touchpad - the pointer will dart about or completely freeze during certain tasks, especially in Firefox; and can only be released by 'waiting' (maybe a few seconds - but it will often freeze again), sometimes hitting the ESC button will release it (but not all the time), or unplug the charger and things tend to settle a bit after the temps go down.


    I can reproduce the issue if the temps climb - but even though the sensors claim the temps are within reason or reducing, the 'symptoms' of kernal-task and freezing pointer, or rainbow wheel still persist. Like the MB is 'lying' about it's true condition. Not to sound like a conspiracy theorist, but I often feel Apple's OS/firmware is designed with some ugly secrets - some of which have been detected by smart people monitoring the machines from the outside (like updating iTunes with tracking of users).


    So there's still a 'heat issue' and probably a secondary electrical charge issue with the battery/charger/inverter/whatever?? I suppose an SMC reset is in order, but I don't recall it ever helping in the past.

  • crazyk4952 Level 1 Level 1

    smit0773 wrote:


    I found the answer to this one.


    I posted it here


    The orginal post was located here:


    This is by Rhys Oxenham.

    Unfortunately, there does not seem to be a plist file for the MacBookPro10,1 (15" retina MBP). So, this fix does not work for those of us with that model.

  • Roberticus1234 Level 1 Level 1



    I'm in the same boat -- I've got the 10,1 and unfortunately there's no profile for it (in the directory that Rhys points us to). But on Rhys' theory the very source of the problem is the profile (which tells the system to run a loop). So, for those of us with a 10,1 -- or a computer not included in the list -- what else can it be?


    Any suggestions would be much appreciated!

  • prajnaji Level 1 Level 1

    Yeh, it was the dust in my computer. Really. It was that simple.

  • crazyk4952 Level 1 Level 1

    Roberticus1234 wrote:




    I'm in the same boat -- I've got the 10,1 and unfortunately there's no profile for it (in the directory that Rhys points us to). But on Rhys' theory the very source of the problem is the profile (which tells the system to run a loop). So, for those of us with a 10,1 -- or a computer not included in the list -- what else can it be?


    Any suggestions would be much appreciated!

    I contacted AppleCare and had one of their techs look at my system logs. He advised me to remove Google Chrome and iStat Menus. He also advised me to delete the spotlight index on my hard drive and re-create it.


    Unfortunately, the problem still happens.


    Since talking with Apple, they have released a few updates specific to the laptops that they released in 2012. After installing these updates, it does seem like the problem happens less frequently.


    As far as people suggesting that it is a dust issue: This problem started happening about a month after I received this MacBook. During this time, my Mac rarely left my desk. If the vents get cloged in this short of a time, then it is a serious design flaw!

  • tingotanca Level 1 Level 1

    "it is a serious design flaw!" - Yes.


    Also: have you a removal of sorts taking place in your immediate surroundings?

  • mangostein Level 1 Level 1

    I've had the kernel_task problem on Leopard and Snow Leopard too.


    I've had some success using Onyx to clear the kernel and extensions cache (in the System tab). Of course, YMMV, but I would be interested to hear if this works more generally.

  • Jasadon Level 1 Level 1

    I hve had a Mac book Air for 3 weeks and yesterday the kernel_task issue started and it runs at 300%+ making the laptop virtually unuseble.


    Is there anyone who could list the possible solutions here in summary? I got confused reading through all these pages and not sure what to do.

  • brexx Level 1 Level 1

    I have the same issue with a 3 month old air i7, 256Gb, 8GB, 13".


    Its been just over a week. Kernel_task getting up to 360%, machine unusable. It rebooted randomly on about day 3 while doing a time machine backup and magically fixed itself for about 10 hours. I shut the lid, it rebooted about 5-6 times and has returned to panic mode for the last 5 days..


    Currently talking to AppleCare, after the backup they now want to do a fresh install? - I have read this still doesn't solve the KT issue due to it being a sensor / hardware fault?


    If it ends up being hardware related, what are your entitlements under warranty at 3 months?

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