If your Mac starts to behave unexpectedly (applications quitting randomly, display dimming for no reason, slow shutdowns, or sometimes your Mac does not start up) a good practice is to reset your Mac parameter nonvolatile random access memory (NVRAM). NVRAM is a small subset of RAM on your Mac used to store certain system settings. Read more about NVRAM on Apple’s Support site.
Note: NVRAM and PRAM are reset the same way below if you are running Mac OS X on your Mac. Both are the same types of ram on Mac’s today.
- Shutdown your Mac.
- Press and hold Alt/Option + Command + P + R and power on your Mac.
- You will see a white screen appear first, then black screen again and your Mac startup chime – indicating another reboot. You just successfully reset your Mac NVRAM and you can release the keys and allow your Mac to boot.