If you see The file couldn't open in protected view error while opening Microsoft Excel, the fixes listed in this post will help you.

If you have sensitive data you'd like to keep from prying eyes in a Microsoft Excel file, the easiest way to protect it is with Excel's built-in password tools.

It is possible to create a macro in an Excel sheet that unlock the sheet which is already protected by a password. Users can easily prepare a document in the sheet and then lock it again with a ...

At the file level, you can password protect an Excel workbook in two ways: You can determine who can get in and who can save changes.