My Book locked in one OS opens in the other

I have two hard drives in my computer, both Win 7.  I’m trying to copy an image from My Book 1140 to the second HD.  When I boot the new WD 2TB, my book is accessable. When I boot from the WD 500GB drive it shows as locked.  What gives

Hello and welcome to the WD Community.

On what drive was the OS originally installed?