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 ...

We give users the option to download these reports as Excel (XLS) files. Normally, when users open these files Excel properly handles the data – they’re simply HTML tables.

If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

Numbers has the ability to open Excel files so you can work on them. You can also export spreadsheets in Numbers so that they are compatible with Excel.

How to convert an XLS file to CSV Let’s say you have the file clients.xlsx and you need it converted to clients.csv to be then uploaded as a client list in your new CRM tool.