I recently purchased a cool new 4 TB external WD hard drive for backups. When I plugged it in and rebooted my computer, I got a black screen and never saw windows boot up. I spent some time looking at various posts but never found anything useful so I thought I'd post my solution here.
Note. the drive worked fine when I plugged it in. I only found a problem when I rebooted the computer. This is a problem as I plan to leave the drive plugged in so my system can make a daily backup each evening to the external drive.