I believe this is a COM related question, but as i'm not sure, i posted it here, not in "ActiveX/COM Help and Support (AutoItX)". I made a very simple script: $oExcel = ObjGet("","Excel.Application") For $y = 1 to 256 For $x = 1 to 65000 $oExcel.Activecell.Value = $x $oExcel.Activecell.Offset(1,0).Select Next $oExcel.Activecell.Offset(-65000,1).Select Next This is a image of it running: There is nothing wrong with this script, but son or not so soon, it gives a error on $oE