I had this working and now it's now saving:

** Instantiate Excel
oExcel = CREATEOBJECT("Excel.Application")

** Open the workbook
oWorkbook = oExcel.Workbooks.Open(sFileName)
 
** Get a reference to the sheet
oSheet = oExcel.Workbooks(1).ActiveSheet

** Select all cells
oSheet.Cells.Select()

** Autofit the cells
oSheet.Cells.EntireColumn.AutoFit()

** Turn on auto filtering
IF NOT oSheet.AutoFilterMode
   oExcel.Selection.AutoFilter
ENDIF
			
** Save the changes
oWorkbook.Save()

** Close the workbook and quit Excel
oWorkbook.Close()
oExcel.Quit()

When the oWorkbook.Close() line is run, I get prompted to save changes. Anyone know what I did wrong?

Also, how do I unselect the selection in code?