An XLSB file is a Microsoft Excel binary file. Microsoft Excel is a spreadsheet software used for productivity in businesses and personal productivity. You convert an XLSB file to an XLS file using the internal Microsoft Excel conversion tool, which is a part of the software. You can convert several file formats to others using Excel's internal conversion tool. An XLS file is an Excel format used for older spreadsheets such as Microsoft Excel 2000 and 2003.
Double-click the XLSB file on your computer. This opens the file and loads Microsoft Excel on your desktop.
Click the "File" menu button and then click "Save As". This opens your "Save" dialogue window. Select "XLS" from the "File type" drop-down box.
Click "Save". The file is saved to your hard drive and converted to the XLS file format.