SMC Reset on Mac: Guide for All MacBook and iMac Models

Introduction / Why This Is Needed

The System Management Controller (SMC) is a microcontroller on your Mac's motherboard that manages power, fans, keyboard backlighting, indicators, and other low-level functions. When it malfunctions, you might experience symptoms such as:

• Fans running at maximum speed for no apparent reason.
• Mac won't turn on, won't wake from sleep, or won't shut down.
• Issues with keyboard or display backlighting.
• Inaccurate battery level indicator on laptops.
• Unexpected shutdowns when running on battery power.

Resetting the SMC (rebooting the controller) often resolves these issues without affecting your data or settings. This guide is for Macs with Intel processors. For Macs with Apple Silicon (M1/M2/M3), the procedure differs and is rarely needed.

Requirements / Preparation

1. Identify your Mac model and T2 chip status (see Step 1 of the guide). This determines the reset procedure.
2. Connect your Mac to a power source. This is mandatory for laptops. For desktop Macs, ensure the power cable is securely connected to both the wall outlet and the computer.
3. Save all open documents and close all applications.
4. Avoid using external devices (monitors, drives) during the procedure unless absolutely necessary.

Step-by-Step Instructions

Step 1: Identify Your Mac Type and T2 Chip Presence

The correct reset method depends on your Mac's generation.

1. Click the  menu in the top-left corner and select "About This Mac".
2. In the window that opens, look at the "Processor" line.
   • If it says "Apple M1", "M2", "M3", etc. — you have an Apple Silicon Mac. This guide does not apply to you. The system controller reset procedure for these Macs is different and is rarely required.
   • If the processor is listed as "Intel" — continue.
3. Click the "System Report" button.
4. In the left column, open the "Hardware" section.
5. Find the "T2 Security Chip" entry in the list.
   • If this entry exists and its status is not "No" — you have a Mac with a T2 chip.
   • If the entry is missing or indicates it's absent — you have a Mac without a T2 chip (older models).

Step 2: Prepare Your Mac for Reset

1. Shut down your Mac normally:  menu → "Shut Down".
2. For laptops (MacBook, MacBook Air, MacBook Pro): Connect the MagSafe or USB-C power adapter. Ensure the charging indicator is lit.
3. For desktop Macs (iMac, Mac mini, Mac Studio): Ensure the power cable is firmly connected to the back of the computer and to the wall outlet.

Step 3: Perform Reset for MacBook Without T2

This method is for MacBook, MacBook Air, and MacBook Pro up to and including 2016 (models without a T2 chip).

1. Ensure your Mac is turned off.
2. Press and hold the following three keys on the left side of the keyboard:
   • Shift (⇧)
   • Control (⌃)
   • Option (⌥)
3. While holding these three keys, press and hold the power button (⏻) on the keyboard (or on the case for older MacBooks).
4. Hold all four keys/buttons for 10 seconds.
5. Release all keys and the button simultaneously.
6. Wait a few seconds.
7. Press the power button (⏻) to turn on your Mac.

Step 4: Perform Reset for MacBook with T2 and MacBook Pro 2016+

This method is for MacBook, MacBook Air, and MacBook Pro from 2018 onward, as well as most MacBook Pro 2016/2017 models with a T2 chip.

1. Ensure your Mac is turned off.
2. Press and hold the power button (⏻) for 10 seconds.
3. Release the power button.
4. Wait a few seconds (5-10).
5. Press the power button (⏻) to turn on your Mac.

Important exception: Some early MacBook Pro 2016/2017 models with a T2 chip (e.g., 15-inch models) may require the method for Macs without T2 (Shift+Control+Option+Power). If the single-button method didn't work, try the algorithm from Step 3.

Step 5: Perform Reset for Desktop Macs with T2

For iMac, Mac mini, and Mac Studio from 2018 onward (with a T2 chip).

1. Shut down your Mac normally.
2. Disconnect the power cable from the wall outlet (or from the power supply if it's removable).
3. Wait 15 seconds.
4. Wait an additional 5 seconds (without reconnecting power).
5. Reconnect the power cable to the wall outlet and to the computer.
6. Wait 5-10 seconds.
7. Press the power button on the case to turn on your Mac.

Step 6: Verify the Result

1. After turning on, your Mac may take longer than usual to complete the boot process (up to 1-2 minutes). This is normal; the SMC is restarting and recalibrating parameters.
2. Check if the symptoms that prompted the reset have disappeared:
   • Stable fan speed.
   • Correct power-on, shutdown, and wake-from-sleep behavior.
   • Functioning keyboard and display backlighting.
   • Accurate battery level indicator (for laptops).
3. If the issue is resolved — the procedure was successful.
4. If the issue persists — repeat the reset, ensuring you selected the correct method for your model. If it didn't help, proceed to the next section.

Potential Issues

• Mac won't turn on after SMC reset.
  • Ensure the power cable is securely connected and the wall outlet has power. Try a different outlet or cable.
  • For MacBook, check that the MagSafe connector or USB-C port is clean and undamaged.
  • If the Mac shows no response to the power button, this may indicate a more serious hardware fault (e.g., motherboard or power supply issues). Contact an Apple Authorized Service Provider.
• Reset didn't help; the problem (e.g., noisy fans) remains.
  • Confirm you used the correct method for your model (with or without T2).
  • Check process activity in Activity Monitor (Applications → Utilities). High CPU load can cause overheating and fan noise.
  • Try resetting NVRAM/PRAM (for Intel-based Macs).
  • Boot into Safe Mode (hold Shift while turning on) to rule out conflicts with third-party software.
  • Update macOS to the latest version.
• After SMC reset on MacBook, the battery won't charge or shows 0%.
  • This could indicate a battery or charging circuit fault. Try resetting the SMC again, ensuring the correct method was used.
  • Check the cable and power adapter. If possible, test charging with a different compatible adapter.
  • If the problem persists, a battery replacement or service diagnostics may be required.

What's Next?

If an SMC reset didn't resolve your issue, I recommend performing the following actions in order of priority:

1. Reset NVRAM/PRAM (for Intel-based Macs). This can help with display settings, startup disk selection, or time-related issues.
2. Boot into Safe Mode. This helps determine if the problem is related to third-party software or kernel extensions.
3. Update macOS to the latest stable version via System Settings → Software Update.
4. Run a disk check using Disk Utility (in Recovery mode).
5. If none of the above helped and the problem appears to be hardware-related (e.g., Mac unresponsive to power, physical damage), contact Apple Support or an Apple Authorized Service Provider.