Resetting PRAM (Parameter RAM) on a Mac is a method of erasing and refreshing specific system settings that may get out of sync, for example, speaker volume, display resolution, startup disk preference, time zone, and other configuration data saved in a small memory area. If you have an Intel Mac, you perform it by rebooting and pressing Option + Command + P + R until you hear the second startup chime or see the Apple logo twice. This can resolve behaviors such as incorrect volume, the wrong startup drive, or display issues without changing any of your files.