Kim, refer the below link

http://www.rondebruin.nl/saveas.htm

If this post helps click Yes
---------------
Jacob Skaria


"Kim Carlsen" wrote:

Hi
I try to save a file in xlsx format, but I get a:
"This extension can not be used with the selected file type. Change the file
extension in the File name text box or select a different file type by
changing the Save as type."

the failing code look like this:
xlWorkBook.SaveAs(fileName, Excel.

XlFileFormat.xlExcel12, misValue, misValue, misValue, misValue,
Excel.XlSaveAsAccessMode.xlNoChange, misValue, misValue, misValue, misValue,
misValue);

What is the correct syntax?
I can get it work with saving to xls file.

Regards
Kim