What Is the SMC and Why Does It Affect Battery?
The System Management Controller (SMC) is a chip on Intel Mac motherboards that controls low‑level hardware functions. It manages:
- Power on, off, sleep, and wake
- Battery charging and health monitoring
- Fan speed (thermal management)
- Keyboard backlighting
- LED indicators
- External port power
If the SMC becomes corrupted – often after a macOS update, improper shutdown, or power surge – it can cause battery‑related problems. Resetting the SMC clears its temporary memory and restores normal operation.
Important: This guide is for Intel Macs only. Apple Silicon Macs (M1, M2, M3, M4, M5) do not have a separate SMC. If you have an Apple Silicon Mac, simply shut down and restart. For other battery drain fixes on Apple Silicon, see our MacBook Pro battery draining fast after update pillar post.
Symptoms That Require an SMC Reset on Intel Macs
If your Intel Mac exhibits one or more of these battery or power symptoms after a macOS update, an SMC reset may help:
| Category | Specific Symptoms |
|---|---|
| Battery | Does not charge when plugged in (charger works on other devices). Battery percentage jumps erratically. Mac shuts down at 20‑30% battery. Charging LED is orange/green but battery level does not increase. |
| Power | Mac does not turn on when pressing power button. Turns on spontaneously without input. Shuts down or goes to sleep unexpectedly. |
| Fans | Fans run at full speed even when Mac is idle and cool. Fans do not spin under heavy load (Mac overheats). |
| Sleep/Wake | Mac does not wake from sleep (black screen, fans spin). Wi‑Fi or Bluetooth disconnects after waking. |
| Ports | USB or Thunderbolt ports stop working until you restart. |
If your macbook pro battery draining fast after update, and you have tried basic fixes (restart, Activity Monitor checks) without success, resetting the SMC is a recommended next step.
For non‑battery symptoms like display issues, see our Mac NVRAM reset guide for power issues.
Before You Reset SMC: Simple Checks to Try First
Resetting the SMC is safe but slightly more involved than a simple restart. Try these steps first:
- Restart your Mac (Apple menu > Restart). Some SMC glitches clear on reboot.
- Shut down, wait 30 seconds, then power on – this alone can reset some SMC functions.
- Reset NVRAM – press Option + Command + P + R at startup for 20 seconds. This handles different settings.
- Update macOS – Apple sometimes fixes SMC‑related bugs in updates. See our macOS update guide (this is a placeholder – you can create later).
If none of these help, proceed with the SMC reset for your specific Intel Mac model.
How to Identify Your Intel Mac Model
To choose the correct reset method, you need to know:
- Is your Mac a laptop (MacBook) or desktop (iMac, Mac mini, Mac Pro)?
- Does it have a T2 chip? T2 chips were introduced in 2018‑2020 MacBooks and some desktops.
How to check for T2 chip:
Go to Apple menu > About This Mac > System Report > Controller. If you see “Apple T2 chip,” use Method A.
No T2 chip? Use Method B (laptops) or Method C (desktops).
If you are unsure, try Method A. It will not harm your Mac. If it doesn’t work, try Method B.
Method A: SMC Reset for Intel MacBooks with T2 Chip (2018‑2020)
This method applies to:
- MacBook Air (2018‑2020)
- MacBook Pro (2018‑2020)
Steps:
- Shut down your Mac. Unplug the power adapter.
- Press and hold the following three keys on the right side of the keyboard:
- Control (⌃) – right Control key
- Option (⌥) – right Option key
- Shift (⇧) – right Shift key
- Keep holding those three keys, then also press and hold the Power button (or Touch ID button).
- Hold all four keys for seven seconds. Your Mac may turn on, then off again. Keep holding.
- Release all keys.
- Plug in the power adapter.
- Press Power to turn on your Mac.
After the reset, your Mac may take longer to boot. This is normal. Test your battery charging and drain.
If the reset does not work, repeat the steps. Ensure you are using the right‑side keys – left side will not work on T2 Macs.
Method B: SMC Reset for Older Intel MacBooks (pre‑2018)
This method applies to:
- MacBook, MacBook Air, MacBook Pro (2017 and earlier)
Steps:
- Shut down your Mac. Unplug the power adapter.
- On the built‑in keyboard, press and hold three keys on the left side:
- Shift (⇧) – left Shift key
- Control (⌃) – left Control key
- Option (⌥) – left Option key
- While holding those three keys, also press and hold the Power button (or Touch ID button if present).
- Hold all four keys for ten seconds. Do not release early.
- Release all keys.
- Plug in the power adapter.
- Press Power to turn on your Mac.
After the reset, test battery behavior. If the battery still drains fast after an update, see our MacBook Pro battery draining fast after update pillar post for additional fixes.
Method C: SMC Reset for Intel Desktop Macs (iMac, Mac mini, Mac Pro)
Desktop Intel Macs have a simpler SMC reset procedure. No keyboard combinations.
Steps:
- Shut down your Mac.
- Unplug the power cord from the Mac itself (not just from the wall outlet – remove it from the computer).
- Wait 15 seconds.
- Plug the power cord back in.
- Wait another 5 seconds, then press the Power button to turn on your Mac.
That is it. This method works for iMac, Mac mini, and Mac Pro models with Intel chips.
For iMacs, also check that the display is not causing power issues. For Mac mini, this reset often fixes USB port problems that can affect battery (e.g., if you use external batteries).
What to Do If SMC Reset Does Not Fix Battery Issues
If your macbook pro battery draining fast after update persists after an SMC reset, the problem is elsewhere. Try these steps in order:
- Reset NVRAM – see our Mac NVRAM reset guide for power issues.
- Run Apple Diagnostics – restart and hold D key. This tests hardware, including the battery and SMC itself.
- Check for third‑party power management software – apps like Turbo Boost Switcher, Volta, or Macs Fan Control can interfere with SMC behavior. Uninstall them temporarily.
- Check battery cycle count – if your battery has over 1000 cycles, it may need replacement. See our MacBook battery cycle count guide.
- Reinstall macOS – as a last resort. See our macOS reinstall without data loss.
For persistent drain after an update, also review the fixes in our pillar post: MacBook Pro battery draining fast after update (Fix 3: Activity Monitor, Fix 5: disable Apple Intelligence, etc.).
SMC Reset vs NVRAM Reset – What’s the Difference?
Many users confuse these two resets. Here is a simple distinction:
| Reset | What It Affects | When to Use |
|---|---|---|
| SMC | Power, battery, fans, sleep, USB, charging | Mac won’t turn on, fans loud, battery not charging, drains fast |
| NVRAM/PRAM | Display resolution, startup disk selection, volume, time zone | Black screen, wrong startup disk, speaker volume stuck, display issues |
If your battery is draining but the Mac otherwise runs fine, try SMC reset first. If you have display or startup problems alongside battery issues, reset both.
For NVRAM reset steps, see our Mac NVRAM reset guide for power issues.
Frequently Asked Questions
Q: How often should I reset SMC on my Intel Mac?
Only when you experience the symptoms listed above. Resetting unnecessarily does not improve performance.
Q: Will resetting SMC erase my data?
No. It only affects low‑level hardware settings. Your files, apps, and macOS remain untouched.
Q: I have an Apple Silicon Mac. Why is this guide relevant to me?
If you have an Apple Silicon Mac (M1‑M5), you can skip SMC reset. Simply shut down and restart. This guide is for Intel Mac owners. For Apple Silicon battery issues, see our MacBook Pro battery draining fast after update pillar post.
Q: SMC reset did not fix my battery drain. Should I do it again?
You can repeat once, but if it does not work after two attempts, SMC is not the cause. Move on to other fixes.
Q: My MacBook’s battery is not charging. Will SMC reset help?
Yes, battery charging issues are classic SMC symptoms. Try the reset. If it still does not charge, the battery or charging port may need replacement.
Q: Does SMC reset fix fast battery drain after a macOS update?
It can, if the update corrupted SMC settings. Try it. But also check indexing and Apple Intelligence (Fix 3 and Fix 5 in the pillar post). Many post‑update drains are software, not SMC.
Q: My MacBook turns on but the battery percentage is stuck. What should I do?
Reset SMC. Also calibrate your battery (older MacBooks only). See our MacBook battery calibration guide.
Related Resources
- MacBook Pro battery draining fast after update – pillar post
- Mac NVRAM reset guide for power issues
- MacBook battery cycle count guide
- When to replace MacBook battery
- MacBook battery health tips
- macOS battery settings guide
- USB devices draining MacBook battery
- Mac Bluetooth battery drain fix
- MacBook charge limit guide
- macOS reinstall without data loss