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.

Find out how you can disable Protected View & remove Read-only in Microsoft Office programs like Excel, Word, PowerPoint, etc, via the Trust Center.

Microsoft Office 2010 includes a new "Protected View" that, by default, will open all Outlook attachments and documents downloaded from the Internet in "read-only" mode.