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.

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 ...

Microsoft on Thursday released a pair of updates to fix a problem with Open XL documents: Microsoft Office 2008 for Mac 12.2.1 Update and Microsoft Office Open XML File Format Converter 1.1.1.

Microsoft went to the Open XML Format for its Office documents beginning in 2007. The Open XML format files are smaller than previous file formats. An Excel Workbook 2007 or 2010 business file ...