Apple System Management Controller
Reset the SMC only after you've tried all other standard troubleshooting. Try each of the following steps in this order before you reset the SMC. Test the issue after completing each troubleshooting step to see if the issue still occurs.
- Press Command-Option-Escape to force quit any application that's not responding.
- Put your Mac to sleep by choosing Sleep from the Apple menu. Wake the computer after it's gone to sleep.
- Restart your Mac by choosing Restart from the Apple menu.
- Shut down your Mac by choosing Shut Down from the Apple menu.
- If your Mac isn't responding, force the Mac to shut down by pressing and holding the power button for 10 seconds. You'll lose any unsaved work in any open applications.
If you're using a Mac notebook computer that's having issues related to power or the battery:
- Unplug the power adapter from your Mac and the electrical outlet for several seconds, then plug it back in.
- Shut down your Mac.
- Remove and re-insert the battery, if it's removable.
- Restart your Mac.
If the issue still isn't resolved, you might need to reset the SMC. See the indicators and steps below.
Indicators that the SMC might need to be reset
After you perform normal troubleshooting, these symptoms might mean that an SMC reset could be necessary:
- The computer fans run at high speed, though the computer isn't experiencing heavy usage and is properly ventilated.
- The keyboard backlight behaves incorrectly.
- The status indicator light (SIL) behaves incorrectly.
- Battery indicator lights, if present, behave incorrectly on Mac notebooks that have a non-removable battery.
- The display backlight doesn't respond correctly to ambient light changes.
- The computer doesn't respond to the power button when pressed.
- A Mac notebook computer doesn't respond properly when you close or open the lid.
- The computer sleeps or shuts down unexpectedly.
- The battery doesn't charge properly.
- The MagSafe power adapter LED doesn't indicate the correct activity.
- The computer is performing unusually slowly, though it isn't experiencing abnormally high CPU utilization.
- Application icons bounce in the Dock for an extended amount of time when opened.
- Applications don't function correctly, or they stop responding after being opened.
Reset the SMC on Mac notebook computers
First, determine whether the battery is removable. Mac notebook computers that have a nonremovable battery 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.