I've recently downloaded the Win10 upgrade. Had been Win 7. I'm trying to create a Recovery Drive on USB. After clicking 'Back up system files..." and Next, the 'please wait' screen appears with the green bar cycling across. After a few minutes, I get a message saying to Connect a USB flash drive with the comment that "The drive must be able to hold at least 8 GB, and everything on the drive will be deleted" and a greyed out Next button. I'm using a USB drive that reports 28.6GB free (a 32GB drive).