I find the solution . maybe help for you. some kext extension (skyguard) cause the reboot. skyguard is a security software developed by 360.inc. You should reboot macOS ,and enter the recovery mode by pressing "command + r" when macOS startup. Next, find the terminal tool in the top menu bar , and open it. Then we can 'cd' the extension directory and 'rm' it. the extension locations : /Volumes/Macintosh HD/Library/Extensions /Volumes/Macintosh HD/Library/StagedExtensions the extension name is : endpointSystemprotect.kext remove it and everything will be ok.

me too. seems that 'com.skyguard.endpoint.systemprotect' cause the problem, but I don't know where it is and how to remove it.