I have A WD book Essential 1Tb unit.If USB cable is pluged in be fore booting up pc the pc hang up part of the way in to the bootup(be fore windows is exe)What is wrorg. That unit work fine if the pc bootedup and pluged in at user login.
More aboutmass storage unit stops
Have you formatted and partitioned in windows before use (What version you using?).
Lot of help on these forums for that product, Smartware etc?