Launch Microsoft Excel Viewer. The Open window opens automatically. Select the XLS file using the integrated file browser. Click the "Open" button to open the XLS file in Microsoft Excel Viewer.

If Excel Online is not working and you see errors Couldn't Open the Workbook, or Request Was Taking Too Long, then see this post for the fix.

How to Open an XLS File in Excel. XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save ...

How to import Microsoft Excel spreadsheets into Apple Numbers This procedure works with .xlsx and .xls file formats. You can also import .csv and tab-delimited files. Launch Numbers (it’s in the ...