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How to Reset SMC on a Mac

Raffi
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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

Typically, an SMC reset helps to resolve many power and hardware-related issues that are otherwise unresponsive to troubleshooting techniques. Resetting a Mac SMC is particularly effective if you’re having the following types of problems:
 
  • 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
If those types of issues describe the problem encountered on the Mac and you have concluded that you need to reset your SMC, we will show you how to do it on any MacBook, MacBook Pro, MacBook Pro with Retina display, iMac, Mac Mini, and Mac Pro. Do notice that the System Management Controller reset instructions are different for MacBook and MacBook Pros if the machine has an internal battery versus a detachable battery; additionally, the procedure is different for desktop Macs than Mac laptops.
 

Reset the SMC of a MacBook Air, MacBook Pro Retina, or MacBook Pro with an internal non-removable battery

This is how to reset SMC on most modern Mac laptops, none of which have a removable battery:
  1. Shutdown your MacBook Air / MacBook Pro
  2. Connect the power adapter to the Mac
  3. On the MacBook / Pro’s keyboard, hold down the Shift+Control+Option keys and the Power button simultaneously.
  4. 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.
  5. Boot your Mac as usual
Here’s the key sequence to hold down:
 
 
Do keep in mind that by resetting the SMC, you will lose power-specific settings, like the time it takes to sleep a Mac and other customizations to power settings. No big deal, but if you have made many changes to your hardware behavior, you will want to adjust stuff like sleep behavior again.
 
The boot time after resetting a machine's SMC can be a bit longer than usual, which is normal. 

Reset the SMC of an iMac, Mac Pro, or Mac Mini

Resetting SMC is different for non-portable Macs, but it’s still easy enough, and the problems it addresses are the same. On any desktop Mac, here is how you reset the System Management Controller:
 
  1. Shut down your Mac
  2. Disconnect the power cord
  3. Press and hold the Mac’s power button for 5 seconds
  4. Release the button
  5. Reattach the power cables and boot the Mac as usual

Reset the SMC of a MacBook or MacBook Pro with detachable batteries

Older MacBook laptops, indicated by having a removable battery, can reset SMC with the following approach:
 
  1. Shut down the MacBook/Pro and remove the battery.
  2. Disconnect the power adapter, and hold the Power Key for 10 seconds.
  3. Release the power key and reconnect your battery and power adapter.
  4. Turn your Mac on.
  5. Let the device boot as usual.

What is SMC anyway?

SMC stands for System Management Controller, a critical low-level component on Mac hardware. Much like the name sounds, the SMC controls and management system hardware for power consumption, battery charging and battery function, thermal activity and fan activity, LED lighting for keyboards and displays, GPU functionality with video mode changes and video output, sleep and wake, and other core hardware functionality on a Mac.
 
Now that your Mac SMC has been reset, the hardware issue you encountered should be resolved unless there is a greater problem or a different issue that needs to be troubleshot separately. Sometimes resetting the Macs PRAM can be effective, too, though there are times when further action is necessary as well. Do note that only Intel Macs have an SMC controller.
 

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