WD My Book 2TB USB 3.0 isn't recognized after full shut down and new start (Win7 Professional 64Bit)

Hi, When I shut down my computer entirely, then my computer doesn’t recognise my new WD My Book 2TB USB 3.0 on the next new start (Windows7 Professional 64Bit). Until now, I have manually unplugged the USB 3.0 plug and after some seconds plugged in again. Then it usually detects the new hardware with drive M:, but sometimes I need some attempts. What is wrong with my settings, so that my computer doesn’t automatically recognize my WD My Book on a new start? (On the other hand, two older WD My Book USB 2.0 external drives are always automatically recognized with a new start with drives K: an L:). Anybody any idea? Many thanks for your help. Regards, Zingeler

Try changeing the drive letter of the my book .