I'm running Kubuntu 18.04 and I'm trying to use woeusb to create a boot memory stick for SuSE Leap. I've set the source to an ISO file for SuSE Leap and the target to /dev/sdb. I've unmounted /dev/sdb1, but I still get a puzzling error message:Source media is currently mounted, unmount the partition then try again. This is particularly mysterious because the source should be mounted.
How can I fix this?