InfoPath - Data Connection Missing Error

Problem: Receive "The data connection is either invalid or missing" when you run the Design Checker after deleting a data connection in an InfoPath form.

Solution: Verify that there are no references to the referenced data connection. IMPORTANT: Check all views! You can delete all references to the data connection in one view but if you don't do the same in the other views, you will continue to receive that error.

I know this seems very simple and I'll admit, it's almost embarrassing to blog about this but I spent several hours on this problem. I had multiple data connections populating drop-down lists that I realized I didn't need any longer so, of course, I deleted them. I removed the reference to the connection from my drop-downs and made sure there were no other reference but I kept receiving that error. I completely forgot that I created another view so I failed to remove the references from that view. The lesson aware of your views!