Hotkeyset() without error checking is very common. Even help file examples omit it sometimes. I've written code to set, check and process  hotkeys in one function. See this example: _HotKey("{ESC}") ; hotkey to exit script. _HotKey("{F1}") ; hotkey to show AutoIt help. _HotKey("{F2}") ; hotkey with missing CASE code. _HotKey("#") ; invalid hotkey _HotKey("{F12}") ; F12 is reserved to the system. While Sleep(100) ; here should be your application. WEnd ; meanwhile, here is a dummy loop. Fun