Quick answer

On an Intel Mac, shut down, turn it on and immediately hold Option, Command, P and R for about 20 seconds, then let go. Apple Silicon Macs have no key combination: they check NVRAM automatically at every startup, so a normal restart is enough.

NVRAM (called PRAM on older Macs) is a small piece of memory that remembers settings such as speaker volume, display resolution, the selected startup disk and your time zone. When a Mac picks the wrong startup disk, forgets its volume, or shows odd startup behavior, resetting NVRAM is one of the first things to try. It does not touch your files.

Intel Macs

How to
  1. Shut the Mac down completely.
  2. Press the power button, then immediately press and hold Option + Command + P + R.
  3. Keep holding for about 20 seconds. On a Mac that plays a startup sound, you can release after the second chime. On a Mac with an Apple T2 security chip, release after the Apple logo has appeared and disappeared for the second time.
  4. Let the Mac finish starting up, then check Sound, Displays, Startup Disk and Date & Time in System Settings and fix anything that reset.

From Terminal

On an Intel Mac you can also run sudo nvram -c and then restart.

Apple Silicon Macs

There is no key combination. An Apple Silicon Mac checks its NVRAM during startup and resets it automatically when it finds a problem, so a normal restart is all you can do.

OpenCore and Hackintosh

If you boot with OpenCore, NVRAM can also be cleared from the OpenCore picker when the Reset NVRAM entry is enabled in your configuration. See how to edit config.plist.

One-click alternative

Optimo keeps the classic Mac Optimizer repairs, including an NVRAM reset, next to its cleaner, resource monitor and disk tools. On older Macs running macOS Mojave or earlier, Mac Optimizer offers the same reset as a single button, along with a kext cache rebuild and a Dock reset.

Frequently asked questions

What is the difference between NVRAM and PRAM?
They are the same idea. Both are a small amount of memory that keeps settings like sound volume, display resolution, startup disk and time zone while the Mac is off. PRAM is the older name.
How do I reset NVRAM on an Apple Silicon Mac?
There is no shortcut. The Mac tests its NVRAM at startup and resets it automatically if something looks wrong, so restarting is the supported answer.
Will resetting NVRAM delete my files?
No. It only clears a few low-level settings, which you may have to set again, such as the startup disk, volume or time zone.
Can I reset NVRAM from Terminal?
On an Intel Mac you can run sudo nvram -c and then restart.