Resetting your Mac System Management Controller (SMC) can be a solution. This is sometimes necessary to restore normal lower level system functionality to your Mac, particularly for power and hardware related troubles.
How to reset the SMC on Mac notebooks
If you have a MacBook Pro (2018), skip ahead to the section that deals with your Mac.
To reset the SMC on a Mac notebook, first determine whether the battery is removable. Most older Mac notebooks have removable batteries. Mac notebooks that have nonremovable batteries include MacBook Pro (Early 2009 and later), all models of MacBook Air, MacBook (Late 2009), and MacBook (Retina, 12-inch, Early 2015 and later). Learn more about Mac notebook batteries.
If the battery is nonremovable:
- Choose Apple menu > Shut Down.
- After your Mac shuts down, press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds. If you have a MacBook Pro with Touch ID, the Touch ID button is also the power button.
- Release all keys.
- Press the power button again to turn on your Mac.