The system management controller (SMC) is responsible for managing the power-related features of Intel-based Macintosh computers. On models that have an Apple T1 or T2 security chip, the SMC is managed by the chip to maintain startup security and prevent unauthorized access.
- The power button.
- Battery and charging.
- Fans and thermal-management features.
- Power to the USB ports.
- Sensors, such as the sudden motion sensor, the ambient light sensor, and keyboard backlighting sensor.
- Sleep behavior when opening and closing the lid of a notebook computer
- Status indicator lights, such as sleep status and battery charging status.
Resetting the SMC
If there are power-related issues with a noteook Mac managed by a SMC, the controller can be reset by shutting down, holding down
SHIFT + CONTROL + OPTION for at least 7 seconds, and then also hold down the power button for at least 10 seconds. The SMC can be reset on a desktop Mac by shutting down, unplugging it from power for at least 15 seconds and then plugging it back in for at least 5 seconds before turning it back on. This process does not affect data stored in NVRAM or PRAM.
- About Startup Security Utility, Apple Support. 2021-01-11.
- Examined: The new MacBook Pro Touch Bar and Apple's T1 authentication chip by Mike Wuerthele, AppleInsider. 2016-10-28.
- How to reset the SMC on an M1 or Intel Mac by David Price, Macworld. 2021-02-04.