A few years back WD was taken to task for creating mandatory virtual CD installers on their external drives. It appears they’re back at it again. New My Book, even after partitioning, still shows a second device (not partition - device) in disk utility and finder with a pester to install the utilities. Since the utilities are buggy and broken, they’ll never be installed, which means the partition will forever appear (multiple actually since I use multiple drives). That’s the end of using WD products.
You could refer to the following link: