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The '''System Management Controller''' ('''SMC''') is a subsystem of [[Intel]] processor-based [[Macintosh]] computers. It is similar in function to the older [[System Management Unit|SMU]] or [[Power Management Unit|PMU]] of non-IntelPowerPC based Macintosh computers.<ref>[{{cite web |title=HT2368: About the SMC Firmware Updates |url=http://docs.infosupport.apple.com:80/article.htmlkb/HT2368?artnumviewlocale=303725en_US |website=Official Apple generalSupport documentation|archiveurl=https://web.archive.org/web/20081223202919/http://support.apple.com/kb/HT2368?viewlocale=en_US on|archivedate=2008-12-23 |url-status=dead }}</ref><ref>{{cite web |title=HT202040: About the SMC Firmware Updates] |url=https://support.apple.com/en-us/HT202040 |website=Official Apple Support |publisher= |accessdate=2018-04-28 |archive-date=2021-05-19 |archive-url=https://web.archive.org/web/20210519004618/https://support.apple.com/en-us/HT202040 |url-status=live }}</ref>
==Overview==
The SMC has roles in controlling thermal and power consumptionmanagement, battery charging, video mode switching, [[Sleepsleep mode|sleep and wake]], [[Hibernationhibernation (computing)|hibernation]], and [[Lightlight-emitting diode|LED]] indicators. It also enables enforcement of the Mac[[macOS]] OS[[End-user Xlicense agreement|End User License]], allowing itmacOS to identify when it is running on non-Apple hardware.<ref>{{cite webpodcast |titlehost=Interview[[Randal withL. AndySchwartz|Randal Hall,Schwartz]] Product|date=2010-08-11 Manager|df=mdy for|title=VirtualBox Oracle|url=https://twit.tv/shows/floss-weekly/episodes/130 VM|website=[[FLOSS Weekly]] VirtualBox|series=130 |publisher=[[TWiT.tv]] |accessdate=2018-04-28 |archive-date=2018-04-28 |archive-url=httphttps://web.archive.org/web/20180428181223/https://twit.tv/floss130shows/floss-weekly/episodes/130 |url-status=live }}</ref>
Apple releases occasional model-specific updates to SMC firmware which correct bugs and defects in the system.<ref>[http://support.apple.com/kb/index?page=search&q=SMC+update Search of SMC update information in Apple's knowledge base]</ref>
* [[Embedded controller]] (EC)
* [[Power management integrated circuit]] (PMIC)
* [[Power Management Unit]] (PMU)▼* [[System Management Unit]] (SMU)▼* [[Apple T2]]
Corrupted SMC firmware, whatever the cause, is not entirely uncommon and may lead to operational problems. Resetting the SMC may resolve certain issues with:<ref>[http://support.apple.com/en-us/HT201295 Intel-based Macs: Resetting the System Management Controller (SMC)]</ref>
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====Fans====
*Cooling fans running at high speed.
====Lights====
*Keyboard Backlight Issues.
*Incorrect behavior with the Status Indicator Lights or Battery Indicator Lights.
*Backlight displays not responding to ambient light changes.
====Power====
*Non-responsive power button
*Unexpected sleep or shutdown
*Battery not charging properly
*MagSafe [[Light-emitting diode|LED]] displays incorrect activity
====System Performance====
*Computer running slowly despite low [[Load (computing)|CPU load]]
*Long "Bounce" times for application icons in the dock.
====Video====
*Unexpectedly switching into or out of target display mode.
====Port Illumination====
*I/O Ports on some late model 2013 Mac Pro's don't illuminate when the computer is moved.
Resetting the SMC is usually accomplished by removing all power from the system for a period of time (by unplugging the [[Mains electricity|mains]] connector or removing the battery) or by operating the power button in a special way. Apple provides model-specific instructions for SMC reset.<ref>[http://support.apple.com/kb/HT3964 Intel-based Macs: Resetting the System Management Controller (SMC)]</ref>
▲* [[Power Management Unit]]
▲* [[System Management Unit]]
==External links==
*[httphttps://support.apple.com/kb/HT1237HT201518 EFI and SMC firmware updates for Intel-based Macs]
<references/>
[[Category:2006Products introductionsintroduced in 2006]]
[[Category:Macintosh computers]]
[[Category:Apple Inc. hardware]]
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