原帖由： Riley Cogdell-Baird ,
Hello. First you’ll need to find what exactly is wrong. It could be many things (Motherboard, SSD, NVRAM etc) First try resetting the NVRAM: # Find the “Command”, “Option”, “P”, and “R” keys on your Keyboard. # Turn on your Computer and hold down Command-Option-P-R together straight away. # Keep holding this down till you hear the start up chime 3 times. # Release the keys. If this doesn’t work, try booting from the recovery: # Find the “command” and “R” keys # Turn on your computer and hold both keys straight away. # Hold them until the recovery starts to boot. If the recovery doesn’t even boot then there is something else wrong perhaps the motherboard.