If I run the following script with my old Excel 2002 it returns "_Application". If I run it with Excel 2010 it returns nothing. As _ExcelBookClose relies on "_Application" it now does not close Excel but returns error 1. Do you think this is a bug in Excel 2010 or in AutoIt? #include <excel.au3> $oExcel = _ExcelBookNew(1) ConsoleWrite(objname($oExcel) & @CRLF) _ExcelBookClose($oExcel, 0, 1)