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

Guide to resetting the SMC (System Management Controller) on Mac to fix power issues, fan behavior, charging problems, and hardware sensor malfunctions. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: 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. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: 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. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: MacBook 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. MacBook without T2 (2017 and earlier): shut down > hold Shift+Control+Option (left side) + power button for 10 seconds > release > power on. Desktop Mac (iMac, Mac Pro, Mac mini): shut down > unplug power cord > wait 15 seconds > plug back in > wait 5 seconds > power on. Apple Silicon Mac: shut down > wait 30 seconds > power on (no manual SMC reset exists — the system resets automatically). After SMC reset: check fan behavior, charging status, and keyboard backlight to verify the issue is resolved. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our Mac Error Codes collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.