Although a mac is a very high-end personal laptop, there will be times when a mac malfunctions, such as the fan rotating at a high speed, the keyboard backlight behaving abnormally, etc. It is most likely that your system management controller SMC is malfunctioning. The problem has arisen, so today I will teach you how to reset the system management controller smc. Interested users should not miss it!
SMC functions
On Intel-based Mac computers, the SMC manages the following and other low-level functions:
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Respond to power button presses
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Respond to display lid opening and closing on Mac laptops
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battery management
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Thermal energy management
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Sudden Movement Sensor (SMS)
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Ambient light sensing
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Keyboard backlight
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Status Indicator Lamp (SIL) Management
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Battery status indicator
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Select external (rather than internal) video source for some iMac displays
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How to tell if you need to reset the SMC
The following symptoms may indicate that the SMC needs to be reset:
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Even though the computer is not under heavy workload and has good ventilation, the computer fan is still spinning at high speed.
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The keyboard backlight behaves somewhat strangely.
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The status light (if present) is behaving strangely.
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The battery light (if present) behaves strangely (on Mac laptops with non-removable batteries).
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The monitor backlight does not respond properly to changes in ambient light.
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Mac doesn't respond when the power button is pressed.
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Mac laptop does not respond properly to lid opening and closing.
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Your Mac goes to sleep or shuts down unexpectedly, and you can't turn it back on.
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The battery cannot be charged properly.
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A MacBook or MacBook Pro cannot be charged via its built-in USB-C port.
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Your MacBook or MacBook Pro doesn't recognize external devices connected to its built-in USB-C port.
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The MagSafe power adapter's LED indicator (if present) does not correctly indicate the status of charging activity.
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Even though the Mac's CPU utilization wasn't very high, it was running incredibly slow.
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Macs that support target display mode cannot enter or exit target display mode properly, or enter or exit target display mode unexpectedly.
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The backlight around the I/O ports on Mac Pro (Late 2013) does not light up when the computer is moved.
Before resetting SMC
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Before resetting the SMC, try the following steps in order. After completing each step, test to see if the problem still occurs.
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If your Mac is unresponsive, hold down the power button until the computer shuts down. All data that is not stored in open applications will be lost. Then, press the power button again to turn on your Mac.
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Press Command-Option-Escape to force quit any unresponsive applications.
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Choose
苹果 () 菜单> "睡眠" to put your Mac to sleep. After the computer goes to sleep, wake it up. -
Choose
苹果菜单> "重新启动" to restart your Mac. -
Choose
苹果菜单> "关机" to shut down your Mac, then press it again电源按钮to turn your Mac on.
If you have a Mac laptop with power or battery issues, follow these steps:
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Unplug the power adapter from your Mac and wall outlet, wait a few seconds, and then plug it back in.
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Choose
苹果菜单> "关机" and wait for your Mac to shut down. -
Remove and reinstall the battery (if removable).
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Press the power button again to turn on your Mac.
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If the issue is still not resolved, you may need to reset the SMC by following the steps below.
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On some keyboards,
Option 键it is also markedAlt.
How to reset SMC on Mac laptop
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If your Mac laptop has the Apple T2 security chip, skip this section and go directly to the T2 section.
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To reset the SMC on a Mac laptop, first make sure the battery is removable. Most older Mac laptops have removable batteries. Mac notebook computers with non-removable batteries include MacBook Pro (Early 2009 and later), all models of MacBook Air, MacBook (Late 2009), and MacBook (Retina Display, 12-inch, Early 2015 and later) . Learn more about Mac laptop batteries.
If the battery is not removable:
Choose 苹果菜单 > " 关机" and wait for your Mac to shut down.
Press on the left side of the built-in keyboard Shift-Control-Option, then press 电源the buttons simultaneously. Press and hold these keys and the power button 10 秒钟. If your MacBook Pro has Touch ID, the Touch ID button is also the power button.
Release all keys.
Press the power button again to turn on your Mac.
If the battery is removable:
Shut down your Mac.
Remove the battery. If you need assistance removing the battery, contact an Apple Authorized Service Provider or Apple Retail Store.
Press and hold 电源the button 5 秒bell.
Reinstall the battery.
Press the power button again to turn on your Mac.
How to reset the SMC on a Mac desktop computer
If your Mac desktop computer is equipped with the Apple T2 Security Chip, please skip this section and go directly to the T2 section.
For iMac, Mac mini, Mac Pro, and Xserve, follow these steps.
Choose 苹果菜单 > " 关机" and wait for your Mac to shut down.
Unplug 电源线.
Wait 15 秒.
Reconnect the power cord.
Wait for 5 秒the clock and press 电源the button again to turn on your Mac.
For unresponsive Intel-based Xserve computers, you can shut down them locally or using remote commands. You can also press and hold the power button for 5 seconds.
How to reset the SMC on a Mac with the Apple T2 Security Chip
For Mac computers equipped with the Apple T2 Security Chip, follow these instructions.
Mac desktop computers with T2 chip
Try the following first:
Choose 苹果菜单 > " 关机" and wait for your Mac to shut down.
Press and hold 电源the button 10 秒bell.
Release 电源the button and wait a few seconds.
Press the button again 电源to turn on your Mac.
If the above doesn't resolve the issue, follow these steps:
Choose 苹果菜单 > " 关机" and wait for your Mac to shut down.
Unplug 电源线.
Wait 15 秒.
Reconnect the power cord.
Wait 5 seconds, then press the power button again to turn on your Mac.
Mac laptops with T2 chips
Try the following first:
Choose 苹果菜Menu > " 关机" and wait for your Mac to shut down.
Press and hold 电源the button 10 秒bell.
Release 电源the button and wait a few seconds.
Press the power button again to turn on your Mac.
If the above doesn't resolve the issue, follow these steps:
Choose Apple menu > Shut Down, then wait for your Mac to shut down.
Press and hold the right Shift 键, 左 Optionkey, and key 左 Control 键 for 7 seconds. Your Mac may turn on and display the Apple logo on the display. While continuing to hold these keys, also press and hold the power button for 7 seconds. If your Mac turned on when you first pressed these keys, it will shut down at this point.
Release all three keys and the power button and wait a few seconds.
Press the power button again to turn on your Mac.