When and How to Reset Mac SMC (System Management Controller)

Mar 24, 2010 - 17 Comments

sad mac reset the smc Ahhhh my Mac isn’t working! So you’ve tried rebooting, you’ve reset the PRAM, you’ve done it all, but your Mac is still behaving strangely. What next? In certain circumstances, try resetting your Mac’s System Management Controller (SMC). This is sometimes necessary to restore normal lower level system functionality to your Mac, particularly if you’re having these types of problems:

* Issues with your Mac’s cooling fans and fan management: fans run constantly 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, 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, target video mode isn’t working properly, 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

So now that you’ve concluded you need to reset your SMC (Note that the SMC is on Intel Mac’s only), here’s how to do it on MacBook’s, MacBook Pro’s, iMac’s, Mac Mini’s, and Mac Pro’s. Notice that the reset instructions are different for MacBook and MacBook Pro’s if you have an internal or detachable battery.

Reset the SMC of a MacBook or MacBook Pro’s with detachable batteries:

* Shutdown the MacBook/Pro and remove the battery
* Disconnect the power adapter, hold the Power Key for 10 seconds
* Release the power key and reconnect your battery and power adapter
* Turn your Mac on
* Let boot as usual.

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

* Shutdown your MacBook/Pro
* Connect the power adapter to your Mac
* On the MacBook/Pro’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
* Boot your Mac as usual

Reset the SMC of a MacBook Air or Retina MacBook Pro

Reset SMC of an iMac, Mac Pro, 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

Hopefully that will clear up your problems, if not it might be worth a visit to the Apple Store or a certified repair center.

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Posted by: Bill Ellis in Mac OS X, Troubleshooting

17 Comments

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  1. [...] When and How to Reset your Mac’s System Management Controller (SMC) – OS X Daily (tags: osx mac troubleshooting) [...]

  2. [...] If all else fails, try this, which has worked for some individuals: * Reset your Mac’s System Management Controller (SMC) : Shutdown the MacBook/Pro, remove the battery, disconnect the power, hold the Power Key for 15 seconds. Replace the battery, reconnect power, and zap PRAM and wait for 2 chimes before letting the keys go. Check out more information on when and how to reset your SMC. [...]

  3. [...] the error message anyway, the message was cleared and everything went back to normal after the SMC power management controller was reset. Anytime your Mac has power management type issues it’s worth giving the SMC reset a shot, it [...]

  4. [...] + Ctrl + Option + PowerButton 3) Пускаш компа. Общо взето, ако нещо не му работи го оправя. [...]

  5. Robert Anderson says:

    OS Lion is destroying Mac Book Pro batteries. Not only is battery life diminished by about 50% but the extra load on the battery is killing the battery itself. Apple is doing their best to deny replacing the ruined batteries but at some point the pressure from customers will make them face this issue, or litigation will.

  6. Ali says:

    special thanks my macbook pro was in that bad mode and with your guide all fixed … love your site

  7. [...] I’ve gotten in the habit of immediately putting my MacBook Air to sleep by shutting the lid, by far the easiest method if you’re on the go. Typically this works without a hitch, but today the Air didn’t sleep when shut. Because the MacBook Air has no moving hard drive or sleep light, I didn’t notice this until I went to use it again about two hours later when I found the machine to be unusually hot to the touch because it never slept as intended. From there on it became a repeatable occurrence, and while I’m not sure of the cause, the solution was just a matter of resetting the SMC: [...]

  8. Rona says:

    Thank you so much. I did lots of searching to find the answer to my problem (fan running, no keyboard or monitor functionality – external keyboard didn’t work either – and you laid out the answer so clearly and simply and it WORKS! MacBook 1,1 Intel Core Duo

  9. Natasha says:

    After searching the Internet forever this is the only thing that worked! Thanks so much!

  10. Required says:

    If following these directions does not work, try powering down, unplugging, then doing the shift, control, option, power thing then restart. Worked for me when the other didn’t.

  11. Emma says:

    so doing this won’t effect the computers hard drive or data at all right? just want to double check before i try anything that i won’t loose any of my information or something like that. thanks!

  12. Omar says:

    This website is awesome :)

  13. Andy says:

    Ok so I have a MacBook (white) and I’ve tried doing this. I’ve had the same problem as the wont sleep thing, but for about a week. Yesterday, I was about to go to the Apple store and try to fix it, but I got it working last minute and didn’t go in. Well, I started getting these restart messages every time my computer did start working, and had to keep doing this until the computer just gets stuck at the white loading screen with a grey spinning wheel under an apple sign(grey) also, this computer has the rounded edges and no, does not have the removable battery. Help!!!!!!!!!

  14. Jonathan says:

    worked for me!
    Fixed my wifi. Macbook is connecting all by herself :)

    thanks

  15. Shally says:

    My mac book pro doesn’t wanna switch on, I have to flush my SMC, please help, it did this once cause of something I plugged in, got it fixed at a hefty price, but they didn’t really change any part so it should be something I can change myself…

  16. JoMO says:

    Thank YOu!!!!!!!!!!!!

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