I just bought the UR12 as well.
Got it working with Cubase Artist 7.
After installing the driver, then open Cubase, a project. Usually for me a box comes up “missing ports”. Then I click on “unmapped” and select UR12.
Also had to go into Devices/Device setup/control panel/ on left panel, select Audio System. Here you can select ASIO Driver, selecting the Yamaha Steinberg USB ASIO.
This helps alot.
Now you will see in the left panel “Yamaha Steinberg USB ASIO” below the Audio System pull down menu.
To continue, in the right panel click on the “unmapped” and select again the UR12 for the ins and outs.
Finally, click on the pull down menu for Devices. Here, you can select VST Connections, then select the ins and outs again.
That should do it. Usually my computer freezes(or CUBASE) so I end task in Task Manager. Then restart Steinberg. Then all should be ready.
Jimbo