Having hardware issues or weird USB issues? Reset the SMC and NVRAM.
Resetting the System Management Controller (SMC)
The system management controller is responsible for managing behaviors 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
- Behavior when opening and closing the lid of a notebook computer
To perform a reset of the System Management Controller (SMC) , please visit Apple Support Article HT201295
Resetting NVRAM or PRAM
NVRAM (nonvolatile random-access memory) is a small amount of memory that your Mac uses to store certain settings and access them quickly. PRAM (Parameter RAM) stores similar information, and the steps for resetting NVRAM and PRAM are the same
Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, and recent kernel panic information. The settings stored in NVRAM depend on your Mac and the devices that you’re using with your Mac.
If you experience issues related to these settings or others, resetting NVRAM might help. For example, if your Mac starts up from a disk other than the one selected in Startup Disk preferences, or a question mark icon briefly appears before your Mac starts up, you might need to reset NVRAM.
To perform a reset of NVRAM or PRAM, please visit Apple Support Article HT204063