Chosen Solution
I replaced my battery using the iFixit tutorial late last year and had no problem until April, when the computer started suddenly shutting down. We can usually just reboot it, but now it has shut down and won’t reboot except for a dark blue screen and the normal reboot sound but after that, nothing. I’ve tried all kinds of resets and tricks, to no avail. Thank you for any help!
I think this might help you out here Troubleshooting Mac Problems: Stuck at the Blue or Black Screen. It’s probably because of drive permission issues.
