How and why to reset the System Management Controller (SMC) of Apple notebooks

Apple recently released some SMC firmware updates for its line of notebooks and many wondered what the hell that was. First of all, let me introduce you to the meaning of the acronym: SMC System Management Controller, or System Management Controller.

New MacBooks Family

Apple's official explanation:

The SMC is an integrated circuit (computer chip) located on the computer's logic board. As the name suggests, she is responsible for the computer's power management. The management unit controls the backlight, the rotation of the hard disk, the modes sleep and wake, some aspects of charging, trackpad control and some inputs and outputs related to the mode sleep the computer.

Over time, SMC configurations can become unusable and generate operational anomalies on the computer. Examples include inability to turn on, wake up from sleep, charge the battery, or recognize the AC adapter, among others.

But be calm: not in any case that you must reset / reset the SMC. In most cases, restarting the machine is sufficient. If a program froze, d Force Quit; if the whole machine froze, give a Force Shut Down (hold the button out for about 10 seconds).

Only after that, should you start an SMC reset. The tip is also very good in cases where the battery of your notebook is not working as it should, even if it is new. Before, however, be sure to read this article.

Now, let's go to the instructions!

MacBooks and MacBooks Pro

  1. If the computer is on, turn it off.
  2. Disconnect the adapter from the outside and remove the battery from the computer.
  3. Press and hold the on / off button for 5 seconds, then release it.
  4. Reconnect the battery and adapter from the outside.
  5. Press the outside button to restart the computer.

MacBooks Air

  1. If the MacBook Air is on, turn it off.
  2. Connect the power adapter to a working power source.
  3. On the MacBook Air keyboard, press Shift + Command + Option (use, obligatorily, the keys on the left side) together with the outside button once.
  4. Wait 5 seconds and press the outside button to turn on the MacBook Air.

Make sure you only perform the procedure with your machine actually turned off.

See more: Mac Pro, iMac and Mac mini. If you own an iBook or PowerBook, Macs with PowerPC processors were managed by Power Management Unit (PMU), check out this article (or more: Power Macs, iMac Flat Panel and Mac mini PPC).

(Via: TUAW.)