Mac NVRAM / PRAM Reset
Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, and recent kernel panic information. If you experience issues related to these settings or others, resetting NVRAM might help.
![Option key](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/macos-nvram-option-key.png)
![plus](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/mac-nvram-add-icon.png)
![Command key](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/macos-nvram-command-key.png)
![plus](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/mac-nvram-add-icon.png)
![P key](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/macos-nvram-p-key.png)
![plus](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/mac-nvram-add-icon.png)
![R key](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/keyboards/macos-nvram-r-key.png)
Shut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P, and R. You can release the keys after about 20 seconds, during which your Mac might appear to restart.
- On Mac computers that play a startup sound, you can release the keys after the second startup sound.
- On Mac computers that have the Apple T2 Security Chip, you can release the keys after the Apple logo appears and disappears for the second time.