I woke up this morning to my Mac automatically shutting down when I try to restart it. It worked well yesterday, but now it turns off when the Apple logo appears on a light gray background. I was able to do the Command + R trick to access recovery mode. I tried to install macOS High Sierra again, but it says that both disks are locked. I do not know how to proceed from this point. If anyone could help it, it would be greatly appreciated!