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 workbooks, but can also use the XLS format.

If you work with multiple Excel files over the course of a workday, and especially if you use a dual-monitor setup, you might wonder how you can launch each Excel file in its own window so you can ...

This month's monster security patch for Office breaks Excel when it tries to open HTML files, and it seems unlikely Microsoft will fix the problem Excel users are reporting an odd bug in the way Excel ...

If you notice that your Excel files are opening in Notepad, then read this post to learn how to fix the issue. The default behavior of a document or file is to open in the application with which it ...

If you use Microsoft Excel on your Mac, you can save the spreadsheets you create and open them in Numbers, Apple’s spreadsheet app. It’s a handy feature to use in case you can’t access Microsoft’s ...

New Outlook fails to open Excel attachments with non-ASCII characters in filenames, and shows an error. Microsoft recommends using Outlook on the web or downloading ...