If you see the “The file couldn’t open in protected view” error while opening Microsoft Excel, the solutions listed in this post may help you resolve the issue ...

Sometimes, Excel ... is not working and won’t open files: Clear browser cookies and cache. Remove problematic add-ons. Check the default file opening behavior. Turn off Protected View.

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 ... How to Fix "Application Not Found" on ...