The first thing listed is to try "Leaving the password field blank" how can you do that? It seems it's required.

I believe the password for my encrypted backup is blank - and even thought the troubleshooting page lists "Leaving the password field blank" as an option to try, it doesn't appear to be possible as the button is not available unless you type at least one character into the password field. If anyone knows of a way to do that, I'd love to hear it.