Fix Fan Noise & Overheating After Upgrading Mac OS X with an SMC Reset
A fair amount of users are reporting that upgrading Mac OS X has caused their Macs to run hotter in general and their fans to constantly engage, creating excessive and unusual fan noise. For users who have just performed an upgrade from 10.6, 10.7, or 10.8, this is usually because of Spotlight and the mdworker & mds process combination, which irons itself out over the course of an hour or so.
If waiting it out hasn’t resolved the heat and fan noise for you, or those Spotlight processes aren’t running, you might want to try resetting the System Management Controller, or SMC. This seems to be particularly effective for MacBook Pro and MacBook Airs that are running hot with considerable fan noise after the OS X installation.
Fix Fan Noise & Heat in OS X by Resetting SMC
For MacBook, MacBook Pro, and MacBook Air models with internal batteries:
- Shut down your Mac
- Plug in the MagSafe adapter
- Press and hold Shift+Control+Option+Power button at the same time
- Release all keys and buttons simultaneously
- Press the power button to turn on your Mac as usual
Apple notes that the little LED light on the MagSafe adapter may change colors or states, or even briefly turn off when you reset the SMC, which could be an easy way to tell if it’s be done successfully.
This tip was left in our comments recently and several readers have responded or emailed us with positive results. To give further backing to the solution, Apple’s support doc lists the following as the first reason to reset the SMC: “The computer’s fans run at high speed although the computer is not experiencing heavy usage and is properly ventilated.
Resetting the SMC is a fairly common trick to fix some of the quirkier power and battery related problems on a Mac, and in many cases it works. If all else has failed, try this out, it just may solve your heat and fan noise issues after updating OS X.
Note: Anytime the SMC is reset you will typically lose custom power settings, so be prepared to go back into System Preferences to readjust Energy Saver settings again.