NVRAM (nonvolatile random-access memory), the updated Mac terminology for PRAM (Parameter RAM), is a small amount of memory that your Mac uses to store certain settings and never clear them out to access them quickly.
Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, and recent kernel panic information.
Method 1: Startup command
If you find that an NVRAM reset might resolve issues, there is more than one way to clean it up. The most common method is by holding down a few keys a second after powering on your Mac:
1. Power off your Mac first.
2. Press your Mac’s power button and then hold these four keys at the same time:
⌘ + option + P + R
3. Continue holding the keys until your Mac restarts for the second time. On older Macs the chime will sound upon restart. On newer Macs, the Apple logo will appear and then disappear.
After pressing the power button, press and hold each of the above-mentioned keys all at once before the first “beep” at the start. When you hear the second “beep”; release the keys.
Method 2: Terminal
Use the Terminal for the same procedure:
- Close all apps and open Terminal (Finder > Utilities > Terminal).
- write sudo nvram -c press Enter.
- Enter the Administrator password press Enter.
- write sudo shutdown -r now and press Enter.
The computer will now restart and that’s it!