macOS NVRAM Reset — How and When to Reset NVRAM Fix

What Does This Error Mean?

NVRAM (Non-Volatile Random Access Memory) stores small amounts of settings that your Mac needs quickly at startup — things like screen resolution, sound volume, startup disk selection, and time zone. When these settings become corrupted, your Mac may behave oddly: wrong volume at startup, wrong resolution, or refusing to boot from the expected drive. Resetting NVRAM clears these settings and lets them rebuild from scratch.

Affected Models

MacBook Air
MacBook Pro
iMac
Mac Mini
Mac Pro
Mac Studio

Common Causes

Corrupted NVRAM settings are causing the Mac to use the wrong startup disk, display resolution, or sound settings
The Mac is not remembering your preferred boot device after restarts
The startup chime volume or system sound volume is stuck or behaving erratically
Display resolution settings are incorrect after connecting a new monitor
Time zone settings keep reverting to an incorrect value

How to Fix It

Reset NVRAM on an Intel Mac. Shut down your Mac completely. Press the power button, then immediately hold Command + Option + P + R. Hold these four keys for about 20 seconds.

On older Macs, you will hear the startup chime twice — that is the signal that NVRAM was reset. On newer Intel Macs without a chime, wait 20 seconds then release the keys.
Reset NVRAM on an Apple Silicon Mac (M1/M2/M3). Apple Silicon Macs do not have a traditional NVRAM reset shortcut. Simply shut down the Mac, wait 30 seconds, and restart normally. The equivalent storage is managed automatically.

On M-series Macs, NVRAM is managed differently and rarely needs manual intervention. If settings problems persist, a DFU restore may be needed — contact Apple Support.
Reconfigure your preferences after the reset. After restarting, go to System Settings > Sound, System Settings > Displays, and System Settings > General > Startup Disk to set your preferences back.

NVRAM reset clears your customizations for these specific settings. You will need to set them again.
Verify the reset worked by checking your startup disk setting. Go to System Settings > General > Startup Disk and confirm your main drive is selected.

If the startup disk setting was the source of boot problems, confirming it here ensures the Mac boots correctly next time.
If problems persist after NVRAM reset, try resetting the SMC. The SMC (System Management Controller) controls power, fans, and other low-level hardware. On Intel Macs: shut down, hold Control + Option + Shift for 7 seconds, then also press power for 7 more seconds, then start normally.

NVRAM and SMC are separate systems. If NVRAM reset does not fix the problem, an SMC reset addresses a different class of hardware setting issues.

When to Call a Professional

Resetting NVRAM is a safe, non-destructive operation. If problems persist after an NVRAM reset, the issue is not with stored settings and requires deeper investigation. Consult Apple Support if the underlying problem continues.

Frequently Asked Questions

Will resetting NVRAM delete my files or apps?

No. NVRAM only stores a small set of system preference values like volume level, screen resolution, and startup disk selection. Resetting it does not affect your personal files, installed applications, documents, or account settings. It is a completely safe troubleshooting step with no risk of data loss.

How do I know if my Mac uses NVRAM or PRAM?

PRAM (Parameter RAM) was used in older Power PC Macs. Intel Macs use NVRAM. Apple Silicon Macs use a different non-volatile storage system. The reset shortcut (Command + Option + P + R) works for both NVRAM and PRAM on older Intel and pre-Intel Macs. For practical purposes, the terms are often used interchangeably in troubleshooting guides.

My Mac keeps booting from the wrong drive. Will NVRAM reset fix this?

Possibly. NVRAM stores the startup disk preference. If the wrong drive is selected there, resetting NVRAM clears the corrupted preference. After the reset, go to System Settings > General > Startup Disk and explicitly select the correct drive. If the Mac continues to boot from the wrong drive after setting it correctly, the issue may be with the drive itself or the boot order in the firmware.