External drive unaccessible after sleep

I went back and forth with WD tech support for months. I tried everything they suggested, and nothing worked. They were quite difficult to work with, since the case would often be assigned to a new tech support representative every time I replied, and even when it wasn’t, they kept responding as if no one had read the conversation thus far. I had to keep repeating myself and answering the same questions over and over again. I finally stumbled upon this thread and was inspired to try uninstalling all WD software (including WD Utilities) from my Mac. It appears that that solved the problem. That’s a shame, because I also use a My Book Thunderbolt Velociraptor Duo, and WD Utilities is the only way to check the RAID status on the Duo.