How to reset NVRAM/PRAM on Mac

Look at the following instruction to reset NVRAM/PRAM on Macbook, Macbook Pro, Macbook Air or iMac.

First let’s learn what are NVRAM and PRAM?
NVRAM stands for Non-volatile random-access memory.
NVRam storages the parmanent information after the OS is turned off. Besides, PRAM saves the temporary data when the OS is operating.
What are saved by PRAM?

  1. Speaker volume
  2. Screen resolution
  3. Startup disk
  4. Kernel-panic error
  5. Status of AppleTalk.
  6. Serial Port Configuration and Port definition.
  7. Port Speed.
  8. Alarm clock.
  9. Application font.
  10. Serial printer location, Autokey rate, Autokey delay.
  11. Attention (beep) sound, Double-click time, Caret blink time (insertion point rate), Mouse scaling (mouse speed).
  12. Menu blink count, Monitor Depth, 32 Bit addressing, Virtual Memory, Ram Disk, Disk Cache

Resetting PRAM/NVRAM Steps

Step 1: Turn Off the Mac.
Step 2: Press the power button.
Step 3: Quickly Press and hold the combination of Command + Option + P + R keys before the white screen appears. Hold the four keys until hearing a “hip” sound and the Mac is rebooted again.