Hello there,
You can simply track this with the help of Event ID 1074: The system has been shut down by a process/user.
This event is written when an application causes the system to restart, or when the user initiates a restart or shutdown by clicking Start or pressing CTRL+ALT+DELETE and then clicking Shut Down.
You can create a simple Powershell script that can identify this Event ID and then trigger a mail. You can also add the time to the script so it can monitor the shutdown up to 4:00 PM.
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