Intercepting spooler timeout  messages

you could try to call FindWindow (for example in an infinite loop and so get a handle of the message window:

while (1)
{
   Sleep(1000); 
   HWND hwnd = ::FindWindow(NULL, "Cartella Stampanti");
   if (hwnd != NULL)
   {
     PostMessage(hwnd, WM_CLOSE, 0, 0);
   }
   // here ad some code that you could stop the loop
}

Select all Open in new window

if closing the message box is not the required action, but to click one of the buttons, things are more difficult since messages to buttons or controls only can be issued by the process (thread) that owns the message box.

the only way to achieve that is by a global hook. that is a dll which needs to be registered (admin rights required) and then was able to hook into the message queue of any process what would allow to find out when the message box was initially shown and then could click on a button programmatically.

Sara