You don't necessarily need Microsoft Excel to work with an .xlsx file Reviewed by Ryan Perian This article explains what XLSX ...

Microsoft Excel has several features designed to help you recover unsaved versions of spreadsheets and prevent data loss. If Excel closes before you save a file, you should see a Document Recovery tab ...

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 ...