I think the reason why it didn’t work on your external drive is that is a different permission to system files. Something to do with usb stuff.
When it comes to backing up your home files, I’m not sure what you mean by home file? Do you mean the home folder? Cause if so I don’t think SaveDesktop can do that as that includes all your files, not just your configs. You’d have to use another tool to move those folders.
Phantomime - Mori Calliope