If Microsoft Excel fails to recognize a file in the XLSX or XLS format, the data contained in the file could be corrupted. When you open a corrupted workbook in Excel, the program should ...

If you are getting the Data source reference is not valid while trying to create a pivot table in Microsoft Excel, see this post for the fix.

How to Open Excel 2007 Files As Separate Windows. 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 ...