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How to Reset NVRAM/PRAM on a Mac

Updated 2026-08-21 · 941 words

To reset NVRAM/PRAM on an Intel-based Mac, shut it down, turn it on, and immediately hold Option-Command-P-R for about 20 seconds. A Mac with Apple silicon does not use this manual key-combination reset; restart it normally and use the troubleshooting options described below.

What does NVRAM or PRAM store on a Mac?

NVRAM, or nonvolatile random-access memory, is a small amount of memory that keeps certain system settings available while the Mac is turned off. PRAM, or parameter random-access memory, is an older name for memory that serves a similar purpose.

Depending on the Mac and its configuration, stored settings can include:

  • Speaker volume
  • Display resolution
  • Startup disk selection
  • Time-zone information

When one of these saved values becomes inconsistent or corrupted, the Mac may repeatedly use the wrong setting during startup. An NVRAM/PRAM reset clears those saved values so macOS can create fresh ones. The reset does not reinstall macOS or intentionally remove personal files, but affected system settings may return to their defaults.

What signs mean you may need to reset NVRAM/PRAM?

A reset is most relevant when the problem involves a setting traditionally stored in NVRAM or PRAM. Common signs include:

  • The Mac selects the wrong startup disk or briefly shows a flashing question mark before starting normally.
  • Speaker volume changes unexpectedly or returns to an unwanted level after a restart.
  • The display starts with the wrong resolution even though the correct resolution was previously selected.
  • The time zone is incorrect after startup and does not remain corrected.

These symptoms do not prove that NVRAM is the cause. A disconnected startup disk, faulty display cable, external audio device, or incorrect automatic time-zone setting can produce similar behavior. Restart the Mac once and check the relevant setting before performing the reset.

What should you do before resetting NVRAM/PRAM?

First, determine whether the Mac uses Apple silicon or an Intel processor. Open the Apple menu and choose About This Mac. The information shown there identifies the chip or processor.

  • Apple silicon: Do not use Option-Command-P-R. Apple’s startup-key guidance limits the NVRAM/PRAM key combination to Intel-based Macs. Restart the Mac normally, then recheck the affected setting.
  • Intel processor: The Option-Command-P-R startup combination performs the reset.

Save open work and shut down normally if possible. Although a reset should not erase documents, keeping a current backup is sensible before any startup troubleshooting. Write down the preferred speaker volume, screen resolution, startup disk, and time zone so they are easy to restore afterward.

Use the built-in keyboard or a wired Mac keyboard when possible. A wireless keyboard may not connect early enough during startup to register the keys. If a firmware password is enabled, Apple advises turning it off before using startup key combinations. If the Mac normally starts in Windows through Boot Camp, select macOS as the startup disk first.

How do you reset NVRAM/PRAM step by step?

Use these instructions only on an Intel-based Mac:

  1. Close your apps and shut down the Mac.
  2. Locate Option, Command, P, and R on the keyboard before continuing.
  3. Press the power button to turn on the Mac.
  4. Immediately press and hold Option-Command-P-R together. Hold all four keys at the same time rather than pressing them one after another.
  5. Keep holding the keys for about 20 seconds. The Mac may appear to restart during this period. On a Mac that plays a startup sound, you may hear the sound more than once.
  6. Release the keys and allow the Mac to finish starting.
  7. Sign in and test the setting that caused the problem.

If the combination does not register, shut down instead of choosing Restart and try again. A wired or built-in keyboard can also help. Do not repeatedly force the Mac off once the reset sequence has begun; let it complete startup after releasing the keys.

What should you check after an NVRAM/PRAM reset?

An NVRAM/PRAM reset can return stored choices to default values. After the Mac starts, inspect the settings connected to the original problem:

  1. Open Sound settings, choose the intended output device, and set the volume.
  2. Open Displays settings and confirm the preferred resolution, refresh rate, and display arrangement.
  3. Open General settings, select Startup Disk, and confirm the disk that should start the Mac.
  4. Open General settings, select Date & Time, and confirm the time zone and automatic settings.
  5. Restart once more and verify that each corrected choice remains in place.

If the setting now remains correct, the reset likely cleared the stored value causing the behavior. If a setting changes again, note exactly when it happens and whether an external display, audio device, or storage disk is connected at the time.

What should you do if resetting NVRAM/PRAM does not work?

If the reset does not fix the problem, disconnect nonessential accessories and restart the Mac. Reconnect devices one at a time; if the problem returns after one device is connected, check that device, its cable, and its manufacturer’s instructions.

For a startup problem, verify the startup disk. If the Mac shows a persistent flashing question mark, a blank screen, or cannot finish starting, use the appropriate macOS Recovery instructions for Apple silicon or Intel. Disk Utility in Recovery can check the startup disk. Safe mode and Apple Diagnostics can also help separate software problems from possible hardware trouble.

Install available macOS updates after the Mac can start normally. If the behavior continues, open {site} and choose the support option for Mac. Describe the symptom, when it began, whether the Mac uses Apple silicon or Intel, and which troubleshooting steps you completed. Do not erase the startup disk or reinstall macOS unless official guidance for the specific startup symptom directs you to do so.