Resetting the System Management Controller (SMC) on your Mac

Sometimes my Mac Book Retina Pro’s fan goes on high for no apparent reason. I checked the memory and CPU usage and I cannot find a good reason for the increased RPM of the system fan inspite of adequate ventilation.

Apple has this to say about this issue, “It is possible that the SMC could encounter an issue that may cause unusual system behavior typically related to the symptoms described below. In some cases, resetting the SMC may be the only correct method to resolve the issue”.

Apparently, the only way to solve this is as follows, which to my surprise I found it works.

  1. Shut down the computer.
  2. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
  3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
  4. Release all the keys and the power button at the same time.
  5. Press the power button to turn on the computer.  
    Note
    : The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.