I always do a hard format of any USB drive for use in a car. Many of them have firmware in the root directory to make them look like a regular hard drive to PCs. Most car audio systems will barf on that set up. I have nearly a dozen SanDisk Cruzers that work flawlessly. I suspect your Duracell drive had firmware or a rootkit and it infected your other USB drive. Hard format both of them. I also use CCleaner to do a drive wipe of new flash drives to make sure they are really clean.