Casio CDP-S90 User Manual page 20

Symptom
Computer Connection
I can't exchange data between the Digital Piano and
a computer.
Action
• Check to make sure that the USB cable is connected to the Digital
Piano and computer, and that the device is selected correctly with
your computer's music software settings (page EN-17).
• Turn off the Digital Piano and then exit the music software on your
computer. Next, turn the Digital Piano back on and then restart the
music software on your computer.
Reference
EN-19