Sorry can't help you with that, but this is why I posted what I did. I thought you just needed the ability to catch system shutdown and if desired cancel it. You can do that with the code in the link and a form (not sure how to cancel it without a form). When the application is closed via whatever means - TaskManager, System Shutdown, Close Button, Code - it fires the Closing event of the form at which point you can determine what caused the close and cancel it if you want. If System Shutdown is called and the form closing event cancels the close it will prevent the system from shutting down.