Groove Agent SE Will Not Load in the Instrument Rack

I was working on a project with two instances of the Groove Agent SE VST. When I returned to my project this morning, the two Groove Agent instruments had disappeared, and in their place it read “No VST Instrument”. I tried to click this text and re-select Groove Agent, but the box would simply vanish and the message “No VST Instrument” would remain.

I checked the Plug-in Information and manager pages, everything seems to be in working order. The MIDI info and track setup are still intact, but my rack just cannot load the Groove Agent instrument. Please Help.

Cubase Pro 8
Steinberg Yamaha UR44
Windows 8.1
Intel i3 2.1 GHz


Which version of Cubase do you have, please? Do you have the latest update Cubase 8.0.20?