Official comment

Hello Theo,
Please uninstall and install the audio driver again.
[Steps]
1. Disconnect your DDJ-RR from the computer.
2. Close rekordbox dj.
3. Open the Control Panel and uninstall the DDJ-RR driver from "Programs and Features".
4. Reboot Windows.
5. Install an appropriate DDJ-RR driver found in the latest rekordbox folder in the computer.
You can find the audio driver in C:\Program Files(or Program Files x86)\Pioneer\rekordbox4.x.x\drivers
6. Connect the DDJ-RR to the computer.
7. Launch rekordbox.
Please note: Do not install the driver while running rekordbox dj. It will cause problems while updating the driver.
If you have any concerns or questions, please reply us.
Thanks,
CRM, Pioneer DJ