My Book failed after just 3 months service. I am using a MacBookPro High Sierra 10.13.1
WD replaced the drive under warranty but I was unable to mount it using the Mac Disk Utility.
I spoke to WD Customer Support. They told me to uninstall WD Drive Utilities and get a new version from their website. I then used the new WD Drive Utility to reformat the drive in APFS. Time Machine promptly popped up and asked if I wanted to use it for backups. For about 24 hours that worked, then Time Machine reported that back ups failed. I tried to use WD Drive Utilities to check the drive but nothing happened at all. I then read this thread and unistalled WD Drive Utilities using the provided uninstall program. Then I opened Time Machine from System Preferences and chose My Drive as the back up disk. The scheduled back up then started 120 seconds later.
I will report back to this thread if there is any change