Is the drive identified as WD in Device manager? If not then it probably isn’t being recognized by Acronis. This version of Acronis is kind of an orphan product. It’s not full featured and it’s based on Acronis TI 2009 so it’s also not that well supported. You might look on the Acronis forums http://forum.acronis.com/forums/acronis-discussion-forums/acronis-home-home-office-products-discussions/acronis-true-image-ho There is a lot of helpful stuff posted there.
Joe