The error message says that Microsoft Excel cannot open the selected file in Protected View. Therefore, if you disable the Protected View in Trust Center settings, the error may get fixed.

You can make Excel always open old spreadsheets in Protected View. Enable or disable Protected View using in-built setting, Group Policy, Registry.

Microsoft's Protected View feature tries to protect you against potentially malicious files and documents. Here's how to use it.

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 ...

Sending Excel files containing crucial financial and business data has risks. To add a layer of protection, you should learn to password protect an Excel file.

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 ...