How to start OS X after a crash (power outage) while entering a keychain password?

Question

macOS

OS X won't start after a sudden power outage while I was trying to enter the keychain password. (the error took off constantly, I do not know from where).
Now, after turning it on, the Apple logo appears, it loads for a few seconds (a strip under the logo), then the Mac just turns off.
It turns out to launch only Safari, after the CMD + R command.

Answer 1

When booting, press Cmd + V - diagnostic messages will be displayed. Basically, there will be reports on the start / successful start of services, but somewhere closer to the hang (unfortunately, not necessarily in the last of the messages), a line or several with error messages will appear. At least you can understand what's wrong.
It’s also worth it, Perhaps, take it to the Service Center - I think it will cost 2-4 thousand rubles (approximately) (by the standards of the MSC).
And also, perhaps it is worth writing a complaint to the public utilities / perpetrators of the power outage - to pay and compensate for damage to repairs - maybe it will work? :)