Hi again, in that case it would appear that the Elements is faulty and needs to be replaced. Check the link below for the steps to create the RMA replacement number.
To keep you updated: I bought DiskWarrior 4.4 and ran it on my Macs … but it does not even see the WD Elements (although Disk Utility sees it but cannot do anything).
Next step / try: I have another WD Elements 500 GB too (but seems to be of another generation, as the USB port is different). I will open the cases and try to put the physical disk that does work in the case of the one that works…