While your Mac will most likely give you years of service with no problems, you may find that from time to time you experience issues with your Mac’s cooling fans running at a high-speed, or your MacBook’s battery won’t charge, or it won’t even turn on. It could be all your Mac needs is to have its System Management Controller (SMC) reset.
What’s a System Managment Controller (SMC)?
The System Management Controller controls and manages your Mac’s system hardware controlling its power consumption, battery charging and battery function, thermal and fan activity, LED lighting for keyboards and displays, GPU functionality, sleep and wake, and other hardware functionality.
Why do I Need to Reset the SMC? (Apologies to Jeff Foxworthy)
If your Mac’s cooling fan(s) run constantly at a high speed, even when no heavy lifting is being done by the CPU, you might need to reset the SMC.
If your Mac isn’t turning on, or it won’t go to sleep, or you’re experiencing random shutdowns and reboots, or your Mac’s battery won’t charge, you might need to reset the SMC.
If your screen on your MacBook or your external display isn’t working, or your Bluetooth and AirPort aren’t working, you might need to reset the SMC. Get the idea?
The method of resetting the System Management Controller on MacBooks and MacBook Pros are different, depending on if the machine has a non-removable internal battery versus a removable battery. Plus, the procedure differs for desktop Macs and laptops. So, pay attention, and don’t try to work ahead.
Note: When you reset your Mac’s SMC it will lose any custom power specific settings, like the time it takes to sleep a Mac and other customizations to power settings. So, you will need to again set any such custom settings you’ve made to you machine following the SMC reset.
SMC Reset Procedure for a Macbook Air, Macbook Pro Retina, or a Macbook Pro With an Internal Non-Removable Battery
- Shut down your MacBook Air or MacBook Pro.
- Connect the power adapter to the Mac.
- On the laptop’s keyboard, hold down the Shift+Control+Option keys and the Power button at the same time.
- Release all keys and the power button at the same time – the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset.
- Boot your Mac as usual. (Note: Don’t freak out if your Mac’s boot-up time after an SMC reset takes a bit longer than usual. It’s normal.)
SMC Reset Procedure for a MacBook or MacBook Pro with a Removable Battery
- Shut down your MacBook/ MacBook Pro and remove its battery.
- Disconnect the power adapter, and hold the Power Button for 10 seconds. Count aloud, if you think it’ll help.
- Release the power button and insert the battery and reconnect the power adapter.
- Turn your Mac on.
- Let it boot as usual. (Note: Don’t freak out if your Mac’s boot-up time after an SMC reset takes a bit longer than usual. It’s normal.)
SMC Reset Procedure for an iMac, Mac Pro, or Mac Mini
- Shut down your Mac.
- Disconnect the power cord.
- Press and hold your Mac’s power button for 5 seconds. (1 Mississippi, 2 Mississippi, 3…)
- Release the power button.
- Reattach your Mac’s power cables and boot it as usual. (Note: Don’t freak out if your Mac’s boot-up time after an SMC reset takes a bit longer than usual. It’s normal.)
Resetting your Mac’s System Management Controller should solve any of a number of minor hardware issues. If you continue to experience ongoing issues, it is always advisable to consult with Apple Support. You can also try to reset your Mac’s PRAM, which can also solve a number of minor issues that arise from time to time.
(Thanks to OSXDaily.com for the original tip)