In some instances, the files open well on different browsers and in file desktop apps like Excel but fail in other Microsoft apps.

A recommended approach to secure your most private documents — whether it’s a PDF, Word file, or Excel spreadsheet — is to lock them with a passcode. While this does help keep sensitive ...

Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.