I guess it depends where you're located. In the EU, it's TWO years, no discussion. Apple has tried to play by its own rules with AppleCare, but has finally lost big time in court in Italy, and there are similar suits on their way in other countries.
Fresh OS install is useless.
I has having the issue with my MBP constantly. That was part of the reason I did a SSD upgrade from HDD. Fresh install of all software. Ran all the updates. Within a day, the Kernel_task was taking over my machine.
I even tried rebooting to my now external HDD over USB. The KT would persist between startub drives, internal and external, SSD and HDD, swapping RAM modules in and out. Nothing seemed to matter. It's like a core boot bug that Apple is unaware of. The fans would sometimes kick in and and I'd never get past a grey screen. So some times the OS wasn't even loading. That's how bad it was.
I've escaped it for some time, a few months now. But I didn't do anything specific.
Because it always semed to accompany overheating, I added a laptop cooler underneath my MBP and that runs all the time. Maybe that's helped the past few months, but I've also had some long rendering video projects where both cores are pushed to maximum for hours, and that hasn't tripped the system back into the KT ****.
So I don't know what it is, but I know what it isn't. It's not an OS reinstall fix.
Currently Being ModeratedFeb 1, 2013 1:58 PM (in response to snow_bunny)
I bumped this thread on 27-Jan. Yesterday i took the Air Book into the Apple Store in Sydney. They were about to re-install the OS but ran diagnostics first and found the light sensor to be faulty.
So they have kept the AIr Book and will be replacing the logic board over the weekend. Incidently the only fix that i have found discussed in 4 similar threads (i.e. kernel_task running over 300%) is replacement of the logic board.
So anyone having these issues should contact apple care or go into an apple store and advise them of this discusssion oof similar experiences. The diagnostics device needs to ascertain if there is a logic board related hardware issue.
Currently Being ModeratedFeb 2, 2013 9:01 AM (in response to snow_bunny)
I was having this problem for several months with my 15" Macbook Pro w/Retina. I would have to do a hard restart about every week. Then, all of a sudden, the problem resolved itself. I have no idea why the problem is no longer happening. I did not do a clean install of the OS.
However, I do have to keep running a repair on my Hard Drive in Disk Utility while booting into recovery mode.
Currently Being ModeratedFeb 5, 2013 5:18 AM (in response to Jasadon)
So my Macbook was in for warranty repair - they were going to replace the logic board. But I got a call tonight and was advised that they would prefer to give me a new one, coincidentally that is my preference too. So new Macbook it is, hoping i never need to post in here again!
Good luck to those with the issue still....hope you get it resolved somehow.
Currently Being ModeratedFeb 5, 2013 8:12 AM (in response to Jasadon)
Given that it affects so many models across so many OSes across so many years, I hazzard to say you may well be back.
My 7 year old MBP which was fine for months, last night ramped high with fans. Yup. Kernel Task ws there again. I shut it down and went to bed.
Came back this morning and so far there's no KT, but it's quite nearly random any more.
Currently Being ModeratedFeb 5, 2013 2:29 PM (in response to Jasadon)
Congratulations Jason, fingers crossed you don't have to go through it again.
Apple made me run a hardware test, it came back with an error code (I googled, it's the temperature sensor) - the rep advised I take it in for repair as it's either dust in the fan or a thermal paste issue (needs to be reapplied?).
I asked if I could have a replacement machine as it's only 3 months old and cost me $2,000 - the senior engineer / support said it would be entirely up to the repairer and if it's as simple as applying thermal paste, probably not - even though i'm within the 3 month 'exchange for new' period! I said I didnt want to keep the machine as its been overheating and had fans running constant for 2 weeks now, am I not legally entitled to a new machine? All I get is "yes, I do apologise, but I can't answer that question for you".
This air replaced a 17" Macbook Pro (Quicksilver) which cost $4500 6ish years ago and went through 3 expanding batteries and major problems with overheating. Apple just doesn't play fair sometimes, the amount of money you pour into their business they seem hesitant in helping you out in return - even when it's their equipment that has been sold with a fault. I have spent so much on every iPhone, iPad, apps, laptops and a desktop - I really thought dropping money on this air was going to give me at least 3 years of no nonsense, solid computing.
Currently Being ModeratedFeb 14, 2013 11:08 AM (in response to snow_bunny)
As posted previously, the slowdown and related overheating were taking place on my 2011 Core i7 MacBook Pro, whereas I have experienced no such problem with a 2010 Core i2 MacBook Pro, nor with a 2007 MacBook Pro, both running around the clock, and I got rid of the issue by opening the case and vacuuming the dust that had accumulated on and around the fans. In the meanwhile, as I also have posted, the 2011 MBP's battery crapped out (out of nowhere, as it never was in use) in the midst of a new outburst of slowdowns and was duly replaced by Apple, after which the machine was again working at full throttle. I assumed that this could partially have been the result of the techs resetting the SMC.
On Jan. 30, Apple issued MacBook Pro SMC Firmware Update 1.6, which turned out to be supported by none of my three MBP's (for a variety of reasons, I always download Apple's update from their site rather than depend on SoftwareUpdate). Two days ago, one more SMC Firmware Update – 1.7 – came out, which like the previous one "addresses a rare issue on some Apple notebooks where a battery that has accumulated more than 1000 charge cycles may unexpectedly shut down or stop functioning", in Apple's own words. This time, though, two of the MBP's were still not eligible, but it had to be installed on the third one. Do I need to say that the eligible MBP is the 2011 machine that has given me all the hassle?
I'd be curious to know, how many among all of you who have posted here have been able to apply any one of these recent updates to their machines? And whether they have noticed a difference in their machine's behaviour afterwards?
Unfortunately, I had just proceeded to the (by now routine) six-monthly vacuuming before the update came out, so it'll be some time before I'm able to see if it also happens to address the slowdown and overheating issue. As a matter of fact, it seems (to the touch) that the machine runs much less hot than I'm used to. Incidentally, I have repeated the vacuuming operation every six months, and while at it, as a precautionary measure, I have also vacuumed the 2010 MBP. Each time, and yesterday was no exception, I've been amazed at how much more dust accumulates in the 2011 machine, considering that they sit in the same office, back-to-back some 20cm from each other. I've tended to attribute this to the heat from two processors (2010 MBP) vs. that released by eight of the kind (2011 MBP), but then who am I to know?
Currently Being ModeratedFeb 15, 2013 8:27 AM (in response to tingotanca)
Wow. I sincerely hope that these firmware updates do adress these issues. They're so pervasive and the hardware is so different between a MBP and an Air, etc. It's got to be software. (IMHO at least.) And software can be updated & fixed.
I just checked Software Update for my 2.16 GHz Core 2 Duo and there's no Firmware updates I haven't installed. And I just recently had a bout with the KT so I'll keep looking forward to a solution. Right now, the big "laptop cooler" I added underneath seems to help me avoid it.
Currently Being ModeratedFeb 17, 2013 2:31 PM (in response to snow_bunny)
Finally after a week and a bit I have my Air back.
First part - Logic board - didn't solve, suspected trackpad.
Second part - Trackpad - didn't solve, suspected screen assembly.
Repairer was stumped, involved another repairer, advanced diagnostics came back with issues in either the logic board (previously replaced and kernal issue still presented) or the power / audio / usb board.
Third part - Power (magsafe connection) / Audio / USB board - problem solved!
No further issues since collecting 3 days ago, the repairer had never seen this issue in a Macbook Air and was quite surprised the power board would be causing the kernal issue.
So - wondering if the magsafe issue you have is related to the magsafe/erratic trackpad issues many face. Maybe it creates electrical spikes or weird grounding issues? I know the 'heat' that it creates can rise substantially when the Air is being taxed by Flash or whatever - then the Kernel problems start up. Just my2cents.
Currently Being ModeratedFeb 17, 2013 4:47 PM (in response to BrothaJay)
No idea, the trackpad was stuttering quite severley, dock items would take 2-3 seconds to expand and animation was jaggered / frame rate 2-3 frames a second when expanded.
Repairer said it could have been the magsafe, the audio line or even an issue with one of the tiny transistors on the board.
I had used my earpods once on the machine and am always careful. There were a couple of moments throughout use (2-3 times in the 2 weeks the kernal was panicking) the audio popped / crackled loudly when the machine was in serious kernal panic. So maybe it was the audio line..
Shame it came to such a process of elimination but I guess that's hardware faults for you.
Currently Being ModeratedApr 2, 2013 12:34 PM (in response to snow_bunny)
I am in kind of the same situation and it is driving me crazy! Lately, the kernel task of my MB pro early 2011 goes over 300% and so it gets almost useless as it runs extremely slow. I took it several times to Madrid apple store,and hardware tests, again more hardaware test, format,cleaning its inside, and total reinstallation of the OSX were performed several times without success: they find nothing wrong but later at home it happens again and again. No more apps installed, new OSX... it can only be hardware, right?
It led to awkward questions and situations as it didnt ever happen when in the apple store, but only at home. Anyway, genius bar people incredibly nice.
I kept insisting, going back and finnally after reading these conversations here and explaining about it at the genius bar, they accepted to change the logic board for me. But sadly, it is happening again, and now i just dont know what else to do. If i take it back to the apple store, i dont know what else to say or explain, so far no problem has been found but it keeps happening. It is so frustrating!!! It is such a shame to have to stop using my Mac normally it is all more than perfect, but once the fan starts sounding loud, i know its back and no more use for a while.
Can anyone help me or give me any advice?? I would really really appreciate it.
Thanks in advance (and sorry for my english)