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.

Open the Excel file you want to protect with a password. Click on File -> Info. Now select Protect Workbook. Select Encrypt with Password from the list. Now enter the password. Confirm it once ...

I tried to set a password on it again, but I’m getting the following error: “This workbook contains Excel 4.0 macros or Excel 5.0 modules.

How to Tell If a Worksheet Is Protected in Microsoft Excel 2003. Protecting a worksheet in Excel 2003 prevents others users from editing it. For example, if you have tracked and charted your ...