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.

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 ...

Twitter used to provide CSV exports of your data, now it's all in machine-readable JSON. How can you use it in Excel?

If you want to view, read and edit JSON files in a readable format, then this post shows how to do it in Windows PC and on the Web.

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 ...

How to convert XLS and JSON files to CSV in Linux with csvkit Your email has been sent Sometimes you just need a quick means of converting a spreadsheet to a comma-separated values file. When you ...

Has someone sent you a .numbers file that you can't open in Excel on your Windows PC? Here's how to edit it using Apple's iCloud apps ...