In Mac OS X, what are the NVRAM and PRAM, and why would I want to zap them?
In a Mac OS X computer, the parameter RAM (PRAM) and non-volatile RAM (NVRAM) are small amounts of RAM that store certain settings. Turning off your computer's power does not clear PRAM and NVRAM; a battery or capacitor on the motherboard keeps them active.
The NVRAM or PRAM can become corrupt and cause problems on your computer. If you're experiencing problems you've been unable to troubleshoot, you can sometimes solve them by "zapping" (i.e., resetting) the NVRAM or PRAM. For instructions, see Apple's About NVRAM and PRAM.
Last modified on November 19, 2013.