Our MacBook (12 inch mid-2017) crashed during an OS update. It had started automatically. The dialogue box says, "The macOS installation couldn't be completed". The installation log started at 15.15.18 and stopped 497 stages later at 15.21.58. I can't determine the problem from the log. Also I can't come out of the installation cycle. Restarting and a shutdown/restart brings back the dialogue box and log. What action should I take to get the MacBook back to normal operation?
Roy Rainford 