Fixing A Mac Booting To Black Screen
Mac’s Screen Going Black On Startup
The common issue reported on many Apple forums is Mac’s screen going black on startup. This is typically followed by recurring “Reset Password” message. The problem appears to be somehow concerned with the battery power circuit with Mac failing to light up the screen.
There is a fairly simple solution to it, though, quite an odd one — involving a flashlight or a lamp. The trick works because your login screen is still there but you can’t see it.
Image Source: Reddit
Shine the flashlight through the Apple logo on the back of your screen. Bringing this extra light should help you see the login icon and you’ll be able to put the cursor in the right spot and log in. The Laptop screen should light up normally right after that. A variant of this solution is to shine a flashlight across the screen from left to right (on the front side of the screen). Try this in a dark room for greater effect.