I bought this product. I connected it to my MacBook Pro and it appeared no problem and it works. I then connected it to my ordinary laptop (Windows Vista) and while it says 'Mass storage device' as the USB device, no drive letter appears in 'My Computer'. I have tried un-installing and re-installing driver, etc.. but no luck. I also tried it on another laptop which is using Windows XP. Again it says 'Mass storage device' but no drive letter appears. I have no problem with other storage devices I connect (including my older 35EV820), so re-installing the OS would not be the solution.
Could it be something to do with 'TimeMachine' on the MacBook? Maybe by connecting it to the MacBook originally caused the problem? It still works fine on the MacBook.
Any advice would be very much appreciated.