Conversion between .LSM and Excel 97XLSX Click File > Save in Excel. When done, in File > Save As click XLSX. Now, Excel will convert this .LSM file into an Excel file. Conversion of .xlsx and Excel 97XLSX (Online) Click File > Save Excel. When done, in File > Save As click XLSX. Now, Excel will convert this .xlsx file into another .xlsx from Excel 97-2003. Do you have any other questions? If you have any question, drop a comment.