How to Reset NVRAM, PRAM, and SMC on Intel and Apple Silicon Macs
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Quick Answer: When and how should I reset SMC and NVRAM on my Mac?
On Intel Macs, reset the **SMC** by holding down Shift + Control + Option + Power while shut down. Reset **NVRAM/PRAM** by holding Cmd + Option + P + R during boot. On Apple Silicon Macs (M1/M2/M3), there is no manual reset; the system performs these checks automatically on restart.
If your Mac is experiencing hardware glitches—such as fans running at full speed, backlights failing, or incorrect display resolutions—resetting the SMC (System Management Controller) and NVRAM (Non-Volatile Random-Access Memory) is the standard resolution path.
Our testing team has analyzed system hardware controller locks in our laboratory. We found that these settings files can become corrupted during system updates or power surges. This guide provides a detailed walkthrough created by our diagnostic experts to reset these controllers on Intel and Apple Silicon MacBooks.
Deciding When to Reset
SMC and NVRAM control different aspects of your Mac. Use the matrix below to identify which controller to target:
| Target Controller | Controlled hardware Systems | Primary Symptoms |
|---|---|---|
| SMC (System Management) | Power routing, battery charging, thermal fans, backlights | Fans running loud, laptop not charging, won't turn on |
| NVRAM / PRAM | Startup disk choice, screen resolution, audio volume, time zone | Incorrect resolution, sound volume stuck, boot loop |
| Apple Silicon PMU | All power and memory configuration settings | System lag, boot loop, charging failure |
If your MacBook is completely unresponsive and refusing to charge or boot, resetting the SMC is often the first step in a broader troubleshooting guide. For a complete checklist, see What to Do When Your MacBook Won't Turn On: Complete Checklist.
Step-by-Step Reset Guide
Resetting NVRAM/PRAM (Intel Macs Only)
- Shut down your Mac completely.
- Press the Power button, and immediately hold down Command + Option + P + R simultaneously.
- Keep holding all keys for 20 seconds. Release the keys once you hear the second startup chime or see the Apple logo fade out twice.
Resetting the SMC (Intel Macs Only)
- For MacBooks with the T2 Security Chip:
- Shut down the Mac.
- Press and hold left Control, left Option, and right Shift for 7 seconds.
- While holding those keys, press and hold the Power button. Keep holding all keys for another 7 seconds, then release.
- Wait 5 seconds, then press the Power button to boot.
- For older MacBooks (Non-T2):
- Shut down.
- Press and hold left Shift + Control + Option, then press the Power button.
- Hold all keys for 10 seconds, release, and boot the Mac.
Intel vs. Apple Silicon (M-Series) Resets
On M-series MacBooks, Apple removed manual resets. The PMU checks the system parameters on every boot. If you experience hardware glitches on an Apple Silicon Mac, simply shut down the laptop, wait 30 seconds, and turn it back on.
If your keyboard itself is unresponsive, preventing you from registering boot commands, see our hardware guide on How to Fix Sticky or Unresponsive MacBook Keyboard Keys.
Frequently Asked Questions (FAQ)
What data does resetting NVRAM delete?
Resetting NVRAM does not delete photos or documents. It only resets startup disk preferences, time zone settings, display resolutions, and system volume levels to factory defaults.
Why won't my NVRAM reset register?
If you are using a wireless Bluetooth keyboard, the keys will not register during early boot sequences. Connect a wired USB keyboard directly to the Mac to perform the reset.
Can an SMC reset fix battery drain issues?
Yes. The SMC manages thermal sensors and battery calibration tables. If the battery calibration is corrupted, resetting the SMC can restore normal charging speeds. For official controller information, see the Apple Support controller reset page. For hardware diagnostics, check the iFixit Mac Repair Wiki.