@f0dder thanks for the tip. I've actually done it on purpose. I use the drive for daily offsite backup (to take home) - as it is easy to loose I thought it adds a bit of additional security. If someone finds it, plugs it in, they might just think "OK then lets format it" :-) You can also disable Windows asking for it if you plug it in. Go to drive management and remove the drive letter - next time you plug it in it will no longer ask if you want to format it (works just for that specific usb device).