Use SetErrorMode function with SEM_FAILCRITICALERRORS parameter. It allows your application don't display error messages, which can appears during executing of your application. In this example, you won't see error "Division by zero".
procedure TForm1.Button1Click(Sender: TObject); var i: Real; begin SetErrorMode(SEM_FAILCRITICALERRORS); i:=1/0; end; For more Win32 Programmer's Reference Download source