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Recovery HD not working, kernel_task >100%

Hello! I have run into a major problem with my iMac and I have no idea what is going on. Help would be greatly appreciated!


The inital problem: I was using my iMac last night, mainly surfing with Safari but with several other applications open in the background (Photoshop, at least ten Safari tabs, Mail, Evernote, iTunes, Spotify, possibly a few others). Suddenly, while reading on a forum, I could no longer scroll the page with my Magic Mouse. In fact, nothing responded at all, no clicks, no keyboard presses (wired, Apple Extended keyboard), no nothing. A minute later, the pointer froze too. I shut down with the power button and restarted.


The first time, the Mac booted into my BootCamp partition. Possibly, I had made that change myself earlier and forgotten about it. Windows 7 started without a fuss, and I then rebooted into OS X.


However, OS X would not load. For over half an hour, only the grey apple and the spinning wheel. Finally, I gave up and tried to boot into the Recovery drive. After a long, long period of waiting, I finally got to the "Welcome" screen where you choose your language. However, neither keyboard nor mouse responded to input. I restarted again, this time trying Safe boot. I got past the grey progress bar, but then it halted again. Tried again, booting into the original System disk (10.5.6), which worked after a long, long time. When at the Welcome screen, the mouse did not work, but I could choose with the keyboard. After choosing, the mouse came alive. I ran Disk Utility, which reported no errors. Set Startup disk to my main partition and restarted. This time (after a long, long time of waiting), I actually came to the login screen on my boot volume. Mouse and keyboard did not respond initially, but came alive after 5-10 minutes. I could then log in. I actually managed to work for a few minutes, saving two recovered PS documents and starting Activity Monitor, before everything beachballed and I had to power down again.


I have now tried this several times. I can only get in to my OS X partition by booting to my DVD, and then choosing the 10.8.2 partition as the Startup drive. I see the same unresponsive mouse/keyboard every time at login or welcome screens. When I get into my 10.8.2 system, I can see in Activity monitor that kernel_task uses 100-110% of processor time, and often another process takes all the rest (mds, CrashReport). Once, I actually managed to quit all my running applications and do a restart from the menu, but it then hanged up on me on the grey "shut-down" screen.


Meanwhile, my Win 7 partition still works like a charm.


Any ideas about what I should do? Should I just give up and restore from Time Machine already? What could be causing the problems with the mouse and keyboard? Why is kernel_task using so much processor time?

iMac (24-inch Early 2009), OS X Mountain Lion (10.8.2), 8GB RAM, ATI Radeon HD 4850

Posted on Oct 31, 2012 5:19 AM

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9 replies

Oct 31, 2012 7:02 AM in response to RRFS

Yes, the Recovery HD (Mountain Lion) was the first thing I tried, and it didn't work (mouse and keyboard unresponsive). I did however manage to Repair the disk and permissions using my original OS X DVD (Leopard). That did not solve my problem, however. Just now, I actually managed to get into the Recovery HD, and ran the repairs again. This time it actualy did repair some permissions, but I don't know yet if that solved the problem. I'm just now using DiskWarrior 4 to repair the catalog.

Oct 31, 2012 8:05 AM in response to Jonas Gabrielson

I have now run DiskWarrior 4 on the iMac and after restarting it does seem to go a bit smoother. Keyboard & mouse seem to respond better at login. I can use the computer somewhat. However, kernel_task is still at 101% processor use, and frequently another app takes up most of the rest -- right now it's Alfred using 91%, before that it was Mail and something called bpd (I think?). I'm now checking System messages for the first time, and it's filled with "sandboxd" denying different file-read-data and the like. I'll see if I can do some Terminal command to see what the kernel is doing later, but now I've got to pick up the kids at daycare! 🙂

Oct 31, 2012 8:10 AM in response to Jonas Gabrielson

I'm sure when Linc responds he'll have a "Real" way to fix your problem but the other day I was having a Kernal_Task run away on my MBA and after running every possibility on ONYX it seems resolved.


OnyX for Mac

http://www.macupdate.com/app/mac/11582/onyx

http://helpdesk.hsc.unt.edu/wp-content/uploads/2010/02/Mac-OS-X-10.6-run-OnyX.pd f




What is a kernel panic,
Technical Note TN2063: Understanding and Debugging Kernel Panics,
Mac OS X Kernel Panic FAQ,
Resolving Kernel Panics, and
Tutorial: Avoiding and eliminating Kernel panics for more details.

Nov 1, 2012 6:54 AM in response to Linc Davis

I took the computer to my local Apple reseller today, and after running the Apple Service Toolkit and resetting the SMC and NVRAM, it works like it used to again. The reset was fortunately free! I'm posting a few links here to possibly help others.


Resetting SMC: http://support.apple.com/kb/HT3964

About NVRAM: http://support.apple.com/kb/HT1379

Using Apple Hardware test: http://support.apple.com/kb/HT1509

Recovery HD not working, kernel_task >100%

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