Be sure to have driver installers for all of your other MIDI devices. This process will require you to reinstall all of your other MIDI devices. If your audio interface has MIDI ports on it, be sure to have that installer available as well.
The first thing you’ll want to do is bring your installation of Cubase up-to-date if it isn’t already. You’ll need to be running version 4.5.2 or higher. You can get the most current installation here:
Next, we’ll need to do some registry editing. Follow the instructions below. If you are not comfortable editing the registry, you will either need to consult an expert or you can call tech support.
1. Go Start > Run and type Regedit.
2. Locate the HKEY_LOCAL_MACHINE > Software > Microsoft > Windows NT > Current Version
3. Under Current Version, click on the Drivers32 key. A list of sub-keys will show up in the right pane; locate the MIDI sub-keys (Midi, Midi1, Midi2 . . . Midi9). These are the registry entries for all of USB MIDI devices.
After this is done, close Regedit. You will now need to uninstall all of your other MIDI devices by going to Start>Control Panel > Add/Remove Programs. You will also need to install the Yamaha USB MIDI Driver version 2.2.3 located here:
Once this is done, you will be required to reboot your computer and reinstall your drivers. When you launch Cubase, go to Devices > Device Setup and highlight the Steinberg CC121 controller. In the right pane, pull down the 2 menus at the top, and you should now have that as a selection in your input and output ports. Choose the controller on those ports, and your CC121 controller will now sync up with Cubase. The light will be solid, and your controller will now have full functionality.