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

With the Excel file open select File in the top-left corner of the screen, followed by Info. Select Protect Workbook, then choose Encrypt with Password.

However, if you open a protected Excel file in the browser edition, you can see hidden formulas, but you can’t modify them. For most sheets, hiding formulas is overkill but easily implemented.

How to Open Excel 2007 Files As Separate Windows. If you work with multiple Excel files over the course of a workday, and especially if you use a dual-monitor setup, you might wonder how you can ...

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.