Excel may not display the XLS file if another option is selected, giving you the impression that it can't open it.

For those cautious about third-party software, LibreOffice is a free and open-source alternative that supports various file types. If the file opens in LibreOffice, save a duplicate, which will then ...

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.

On the right side, select the Open checkboxes for the file types that you want to open in the Protected View. Now, select the Open selected file types in Protected View radio button at the bottom.

Why won’t Excel open in the browser? There are various reasons your workbook might not open in Excel on your browser. This can be because of an issue with the browser you are using. Also, it might be ...

If you are unable to open an Excel file? You can use this tool to repair your corrupt Microsoft Excel files easily the right way.

The File Couldn't Open in Protected View [Excel, Word] If disabling Protected View fails to fix this, use a file repair software.

Why Can't I Insert a File in Microsoft Excel?. Along with the formulas, functions, calculations and data you enter into a Microsoft Excel worksheet, the program also accepts files from other ...