this problem comes from nowhere,

the pcroom pc OS updated to windows 11 with software level restore program,

however, some PCs keep restart itself after proper shutdown by manual or remote command, for example, by Veyon

tried power option modification, turned off wake on lan, even stop system restarting while failure on sysdm.cpl

finally a youtube video method works,

that is: fix registry settings on windows OS level.

1. call registry editor, in tranditional chinese envirorment, need to search "登錄編輯程式"

2. find HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

3. modify value of PowerdownAfterShutdown to 1, default setting is 0.

4. save configuration.

done, looks like it works, now the PCs are all gracefully shutdown.