Quote Originally Posted by Yatta View Post
If your Mac starts up to a question mark - Apple Support

Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
Turn on your Mac and immediately press and hold Command (⌘) and R to start up from macOS Recovery.
While in macOS Recovery, use Disk Utility to repair your startup disk.
If Disk Utility found no errors or repaired all errors, take either of these actions:
Reinstall macOS
Restore from a Time Machine backup
If you still need help, please contact Apple Support.
Same thing happened to our Mac air last week, Wala kaming back up na time machine and it cannot locate the hard disk after doing the above, after a long rest nag normal sya, but then after several days totally nasira na, it dies several minutes after being turned on.