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MacBook Pro fan running

On my MacBook Pro the fan continuously runs high speed while I'm using it. Any suggestions?

MacBook Pro, Mac OS X (10.7.5)

Posted on Jun 17, 2013 2:07 PM

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16 replies

Jun 17, 2013 2:10 PM in response to loganRN

Open Activity Monitor in the Utilities folder. Select All Processes from the Processes dropdown menu. Click twice on the CPU% column header to display in descending order. If you find a process using a large amount of CPU time (>=70,) then select the process and click on the Quit icon in the toolbar. Click on the Force Quit button to kill the process. See if that helps. Be sure to note the name of the runaway process so you can track down the cause of the problem.

Jun 18, 2013 12:04 PM in response to loganRN

Install iStat Menus 4.05 and find out what your operating temperatures are. If they are not high, then you may have a bad sensor that needs repair.


You might try running hardware diagnostics.


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Jun 18, 2013 3:22 PM in response to loganRN

Yep, temperatures are all on the mid to low range so you definitely have runaway fans. Hoping it is a software issue, I'd start by doing an SMC and NVRAM reset.


If that don't cure it, do a Safe Boot: restart and hold down Shift till it finishes starting up. Will take a long while. Only Apple software will be loaded. Since iStat won't load, you'll have to play it by ear to see if the fans are still loco. If the fans quieted down, try rebooting normally. Then if the fans stay quiet, there was some sort of corruption in a cache or setting that got cleared out by the Safe Boot. Else, if they start up again, you have some third party code causing it and you now have the chance to play Digital Sherlock Holmes....


If the fans keep going nuts throughout all the above, then Kappy's right, some bit of hardware is kaput and a trip to the Store is inevitable.

Jun 18, 2013 3:45 PM in response to loganRN

The temps are OK, so there is no reason for the fans to run at full speed unless there are bad sensors or sensor failure, hence, the suggestion to have it serviced before the fans die. Since you seem to have explored the software possibilities, the next thing to check out are the hardware possibilities.

MacBook Pro fan running

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