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SMC Reset — Mac Hardware Controller Reset for Power and Fan Issues

Warningsystem

Overview

Guide to resetting the SMC (System Management Controller) on Mac to fix power issues, fan behavior, charging problems, and hardware sensor malfunctions.

Key Details

  • The SMC controls power management, battery charging, fan speed, LED indicators, and sleep/wake behavior
  • SMC reset is different for MacBooks (with and without T2 chip) vs desktop Macs
  • Apple Silicon Macs do not have a traditional SMC — they handle these functions differently
  • SMC reset should only be performed after other troubleshooting steps fail
  • Common symptoms of SMC issues: fans running at full speed, Mac not charging, sleep/wake problems

Common Causes

  • Mac fans running at maximum speed regardless of actual temperature
  • MacBook not charging despite being plugged in with a working charger
  • Mac not turning on, not waking from sleep, or shutting down unexpectedly
  • Keyboard backlight, status LED, or display brightness not working correctly

Steps

  1. 1MacBook with T2 chip (2018+): shut down > hold Control+Option+Shift (left side) for 7 seconds > then also hold power button for 7 more seconds > release all > wait 5 seconds > power on
  2. 2MacBook without T2 (2017 and earlier): shut down > hold Shift+Control+Option (left side) + power button for 10 seconds > release > power on
  3. 3Desktop Mac (iMac, Mac Pro, Mac mini): shut down > unplug power cord > wait 15 seconds > plug back in > wait 5 seconds > power on
  4. 4Apple Silicon Mac: shut down > wait 30 seconds > power on (no manual SMC reset exists — the system resets automatically)
  5. 5After SMC reset: check fan behavior, charging status, and keyboard backlight to verify the issue is resolved

Tags

smcresetpowerfanbattery

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Frequently Asked Questions

Try an SMC reset when fans run full speed constantly, MacBook does not charge, Mac does not turn on or wake from sleep, or hardware indicators (LEDs, backlight) behave incorrectly.