Im also wondering if it has anythign to do with the drive being usb 3.0 the cable and manufature says usb 3.0 capatable with usb 2.0 and that it should not matter. The older computer is a mac book pro using vmware 3.1.5 and the new computer is a macbook pro using the new VMware 5.0.2. im guessing it has to do with VMware fusion because that is the only thing that has changed between computers. Ive gone over all the drivers for the external drive and its all there but every time I connect it to windows xp the windows xp then produces a error saying usb device not recognized and then the drive changes from a drive to an unknown device under Universial serial buss controllers in device manager. The oddest part is that I have an older computer running VMware Fusion 3.1.5 with windows xp and it runs just fine. I have a WD 1t my passport external HD and it will not show up in windows xp.

So ive been on Microsofts forums and support and WD forums and support and this is the last stop to try and fix this problme.