@TomMartinak wrote:
I have a file on my usb \.dropbox.device which is messing up my backup. Where is it? So I can delete it. And how do I keep it from showing up again
It will be a hidden file in the root of your drive. If it's truly messing up a backup job it would be best to just add an exclusion for it in your backup software. Any removable drive you connect to your computer will get that file as long as Dropbox is installed and running.
You can go into Dropbox Preferences and tell it not to ask about backing up external drives that you plug in, and you can change the autoplay settings in your OS so Dropbox isn't used when you connect a drive, but I don't know if that will completely prevent the file from showing up.