Update: If you're running a Mac with Apple Silicon (M1, M2 Chip, etc.) you only need to fully restart your Mac to reset the SMC. This function is now built into the normal reboot sequence.
This article originally appeared in: http://osxdaily.com/2010/11/15/reset-pram-mac/
You have tried rebooting, resetting the PRAM, and done it all, but your Mac is still behaving strangely. What next? In certain circumstances, 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.
We’ll show you exactly how to reset the SMC on any Mac (and any version of OS X) and the type of problems it may resolve.
When & Why Reset SMC on a Mac? Some Common Hardware Reasons
- Issues with your Mac cooling fans and fan management: the fans constantly run at high speed, fans run high despite low CPU usage and adequate ventilation, fans not working at all, etc.
- Power management and battery problems: Mac isn’t turning on, sleep isn’t working, random shutdowns and reboots, the battery isn’t charging, Mac won’t wake from sleep, etc.
- Light problems and improper lighting management: battery indicator lights aren’t working, display backlighting isn’t adjusting to ambient light changes, keyboard backlights not working, etc
- Video and external displays not working: display brightness functionality not working properly, the target video mode isn’t working properly, the external display isn’t working, etc.
- General performance and functionality problems: abnormally sluggish behavior despite no CPU or disk usage, external ports not working, airport & Bluetooth aren’t showing up, external devices are not being found, etc
Reset the SMC of a MacBook Air, MacBook Pro Retina, or MacBook Pro with an internal non-removable battery
- Shutdown your MacBook Air / MacBook Pro
- Connect the power adapter to the Mac
- On the MacBook / Pro’s keyboard, hold down the Shift+Control+Option keys and the Power button simultaneously.
- Release all keys and the power button simultaneously – the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset.
- Boot your Mac as usual
Reset the SMC of an iMac, Mac Pro, or Mac Mini
- Shut down your Mac
- Disconnect the power cord
- Press and hold the Mac’s power button for 5 seconds
- Release the button
- Reattach the power cables and boot the Mac as usual
Reset the SMC of a MacBook or MacBook Pro with detachable batteries
- Shut down the MacBook/Pro and remove the battery.
- Disconnect the power adapter, and hold the Power Key for 10 seconds.
- Release the power key and reconnect your battery and power adapter.
- Turn your Mac on.
- Let the device boot as usual.