My retina MacBook Pro sometimes crashes randomly. It happened again yesterday and this time it refused to boot up to the login screen. After fighting it for 4 hours, trying out safe mode, recovery mode, single user mode, disk repair, I finally figured it out with some Google help. If you notice that your logs are noting loginwindow crashes due to lsregister and it keeps repeating, what you might want to try is delete your LaunchServices cached which looks like /private/var/folders/XX/YY/C/ See here for more details.