My Book Essential + Mountain Lion + Mid 2012 Mac Book Pro (Retina display)

I am having the same problem.  My hard drive works fine on my older MacBook Pro, but will not work on the one I just purchased (which is my wife’s system). There is a firmware upgrade available at the WD site, and this did help. Before the firmware upgrade the MacBook did not recognize the device. Now, it recognizes it but as soon as I try to write to it the device is disconnected.  This behavior is the same in Disk Utility and CClone.