Official comment
Hello Fabry,
DDJ-RZ engineers advised you to try updating Windows to the latest version using Windows Update in order for Windows to recognize DDJ-RZ driver.
Because we assume that the Windows you use has not been updated to the latest since March 2, 2015, Windows recognized DDJ-RZ driver where an invalid digital signature is used.
Thank you very much for your kind understanding and cooperation in advance.
Best regards,
CRM, Pioneer DJ