NVRAM is a type of RAM that retains data after the host device's power is turned off. ( in contrast to RAM ). NVRAM is used to store values like: brightness, volume, computer name, Find My Mac’s ID, etc… In Windows and Linux these values aren’t stored in NVRAM but on the HDD, as most PCs don’t have NVRAM. OS X utilizes NVRAM to run many services like iMessage, FaceTime, boot device, etc…   Said that, before proceeding, make sure you do not have Emuvariable installed in the EFI, delete