What is the SMC?
It’s an acronym that stands for System Management Controller. It’s only on Intel based Macs and it’s main purpose is to keep your Mac running smoothly and with minimal noise. It controls things like fan speed and power. It is also responsible for controlling lights on the keyboard and detecting ambient light through the webcam. It’s a separate chip on the main board of your Mac. Normally it’s something that you don’t even know exists until you start having problems and you learn about it through Google and research.
Symptoms of a Corrupt SMC
When you start experiencing weird behavior on your Mac, it could be SMC related. Here is a list of symptoms that might indicate your SMC needs resetting.
- Your fans are running at high speed all the time. Even when your Mac is not being heavily used.
- The keyboard backlight doesn’t behave properly.
- The screen brightness does not respond to ambient changes in light.
- Your computer doesn’t do anything when your press the power button.
- Your computer doesn’t go to sleep or respond properly when you close the lid, or it doesn’t wake up from sleep mode.
- Your computer sporadically goes to sleep or powers off.
- The battery does not seem to charge.
- The LED indicator on the charger doesn’t indicate the proper activity or doesn’t come on at all.
If you are experiencing any of these, then there’s a good chance you might need to reset the SMC.
Reset the SMC of Macbook or Macbook Pro with Removable Batteries
Shut down your Mac and remove the battery and disconnect the AC adapter.
Hold the power key for at least 10 seconds and then release it.
Reconnect your battery and AC adapter.
Turn your Mac on and it let it boot as usual.
Reset the SMC of Macbook or Macbook Pro with Internal Batteries
Shut down your Mac
Connect the AC adapter.
Press and hold the SHIFT, CONTROL, OPTION and Power Buttons down all at the same time.
Release them all at the same time.
Boot your Mac as usual.
Reset the SMC of iMac, Mac Pro or Mac Mini
Shut down your Mac and disconnect the power cord.
Press and hold the power button for at least 10 seconds.
Plug the power cord back in and boot your Mac as usual.
Additional Method to Reset the SMC
I have ran across this issue a couple of times on a Macbook Pro. Basically the battery was completely dead and the laptop was experiencing the issues where it wasn’t charging, the AC adapter LED wasn’t displaying and it wasn’t responding to the power button. So, the standard way of resetting the SMC was not working. In this case, I removed the bottom cover and on the mother board are two contacts near the area where the AC adapter plugs into. It’s actually labeled SMC reset. Taking a small flat head screwdriver or paperclip, you can bridge this two contacts and it will reset the SMC as well.
Hopefully if you were having problems, you were able to resolve it by resetting the SMC using one of the methods here.
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