Introduction
The following symptoms may mean an SMC reset is needed:
- Your computer's fans are running at high speed, even if the computer is not under heavy load and is properly ventilated.
- Keyboard backlight works incorrectly.
- Status light, if present, is malfunctioning.
- Battery LEDs, if present, work incorrectly (for Mac laptops with a non-removable battery).
- The display backlight does not react correctly to changes in brightness.
- Your Mac does not respond when you press the power button.
* Your Mac laptop does not respond properly when you close or open the lid.
* Your Mac goes to sleep or shuts down unexpectedly.
- The battery does not charge properly.
- MagSafe Power Adapter LED does not indicate correct activity.
- Your Mac is abnormally slow, although its processor is not heavily used.
- A computer that supports the target display mode does not switch between modes as expected, or switches between modes unexpectedly.
- Mac Pro (Late 2013) I/O ports are not illuminated when moving the computer.
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            If your Mac isn't responding, force shut it down by pressing and holding the power button for 10 seconds. Any unsaved data in open applications will however be lost. 
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            Press Command+Option+Esc to force quit any unresponsive app. 
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            Put your Mac in sleep mode by choosing Sleep from the Apple menu. Wake the computer after it went to sleep mode. 
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            Restart your Mac by choosing Restart from the Apple menu. 
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            Shut down your Mac by choosing Shut Down from the Apple menu, then turn it back on. 
 
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            Unplug the Mac's power adapter and power outlet for a few seconds, then plug them back in. 
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            Shut down your Mac. 
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            Remove and reinsert the battery (if removable). 
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            Restart your Mac. 
 
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