How to reset the SMC of your Mac

Resetting the system management controller (SMC) can resolve certain issues related to power, battery, fans, and other features.


This article applies only to Mac computers with an Intel processor.

Reset the SMC on computers that have the T2 chip

If your Mac has the Apple T2 Security Chip, follow these steps. If you need help, contact Apple Support. 

Notebook computers with the T2 chip

Before resetting the SMC, try these steps:

  1. Shut down your Mac.
  2. Press and hold the power button for 10 seconds, then release the button.
  3. Wait a few seconds, then press the power button to turn on your Mac.

If the issue persists, follow these steps to reset the SMC:

  1. Shut down your Mac.
  2. On your built-in keyboard, press and hold all of the following keys. Your Mac might turn on.
    • Control  on the left side of your keyboard
    • Option (Alt)  on the left side of your keyboard
    • Shift  on the right side of your keyboard
  3. Keep holding all three keys for 7 seconds, then press and hold the power button as well. If your Mac is on, it will turn off as you hold the keys.
  4. Keep holding all four keys for another 7 seconds, then release them.
  5. Wait a few seconds, then press the power button to turn on your Mac.

Desktop computers with the T2 chip

  1. Shut down your Mac, then unplug the power cord.
  2. Wait 15 seconds, then plug the power cord back in.
  3. Wait 5 seconds, then press the power button to turn on your Mac.

 

Reset the SMC on other computers

If your Mac doesn't have the Apple T2 Security Chip, follow these steps. If you need help, contact Apple Support. 

Notebook computers with a non-removable battery

This applies to MacBook Pro models introduced in mid-2009 through 2017, MacBook Air models introduced in 2017 or earlier, and all MacBook models except the MacBook (13-inch, Mid 2009).

  1. Shut down your Mac.
  2. On your built-in keyboard, press and hold all of these keys:
    • Shift  on the left side of your keyboard
    • Control  on the left side of your keyboard
    • Option (Alt)  on the left side of your keyboard
  3. While holding all three keys, press and hold the power button as well.
    Notebook keyboard with all 4 keys pressed
  4. Keep holding all four keys for 10 seconds.
  5. Release all keys, then press the power button to turn on your Mac.

Notebook computers with a battery that can be removed

This applies to all MacBook Pro and MacBook models introduced in early 2009 or earlier, as well as the MacBook (13-inch, Mid 2009). 

  1. Shut down your Mac.
  2. Remove the battery. (If you need help removing it, contact an Apple Store or Apple Authorized Service Provider.)
  3. Press and hold the power button for 5 seconds.
  4. Reinstall the battery.
  5. Press the power button to turn on your Mac.

Desktop computers

  1. Shut down your Mac, then unplug the power cord.
  2. Wait 15 seconds, then plug the power cord back in.
  3. Wait 5 seconds, then press the power button to turn on your Mac.

 

About the SMC

The system management controller is responsible for managing behaviours related to these features:

  • Power, including the power button and power to the USB ports
  • Battery and charging
  • Fans and other thermal-management features
  • Indicators or sensors such as status indicator lights (sleep status, battery charging status, and others), the sudden motion sensor, the ambient light sensor, and keyboard backlighting
  • Behaviour when opening and closing the lid of a notebook computer

Resetting the SMC doesn't affect the contents of NVRAM or PRAM.

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