The tool has lots of macros which run in the background to do various things. This is much more than a spreadsheet, it is more like an app, which happens to run in Excel. As such, if lots of changes were made to the sheet like adding rows, columns, sheets etc, then the macros wouldn't work properly. Therefore the tool has been protected to prevent it from being modified in ways which may stop it from working. If you are prompted for the password then you must be doing something in a way in which the tool wasn't intended, please watch the video to remind yourself how to use the tool.