The installation of the driver software might be incomplete or the connection might be causing a problem.

If you’ve already installed the driver software, try again using the following procedure:

■Windows

1. Close rekordbox and disconnect the OPUS-QUAD from your computer.

2. Open the control panel (or [Start] > [Settings] > [Apps]) and uninstall [OPUS-QUAD Driver].

3. Close Windows.

4. Disconnect other USB devices, USB hubs, etc.

5. Start Windows.

6. Download the driver software from [here].

7. Install the driver software again.

　*An error will occur when the license agreement screen is displayed and you try to proceed without clicking "I agree".

8. Connect the OPUS-QUAD to another port without using a USB hub, etc.

If you still can't set [AUDIO], the problem might be caused by operating system settings, etc.

See cases 3 and 6 in the guide [here].