Can't expand drive on communicator U3

Hi, just bought a communicator U3 on amazon to upgrade an older USB 2.0 dock to a 3.0 one. I just got a brand new desktop running window 8 and it has usb 3.0. My 2.0TB drive won’t expand in windows explorer. This drive worked fine literally minutes ago in the old dock. Pluggable will assign a drive letter, and properties shows the correct size and space on the disc, but the “Expand” line is grayed out, and double-clicking does nothing. Any ideas?