Why does Excel warn me about an external data connection when I open it?? Is this spreadsheet sending data to you or someone else?
No, your data is not being shared. The spreadsheet uses Excel’s Power Query to create a large table of all of the registers so that the Dashboard and Report screen can consolidate that data while also offering filter buttons (slicers) to hone in on the data that you want to see at any moment. It’s unfortunate that Excel considers its own feature (Power Query) as an external data connection, but it does! The spreadsheet does not send any data to me nor to any outside service. One of the reasons I like using a spreadsheet for my finances is that I don’t want my data shared with any 3rd party! I’m sure you feel the same.
When you’re in Excel, there’s a menu choice called Data. And under that menu choice, there are buttons to see the Queries & Connections. It will show queries for the registers along with an “All_Registers” which is the combination of all of the registers for the benefit of the dashboard and report. But there are no connections to the outside world nor to any Internet service.