Yamaha RP-U100 Owner's Manual page 60

Opening Page 31/68 ページ
Error Message at Startup
The error message "Can't find RP-U100 !!" appears when the main unit and
personal computer are not connected with a USB cable.
Connect the RP-U100 unit to the computer with a USB cable when using the
application.
Even if the RP-U100 unit and computer are connected by a USB cable, the error
message will appear if the power cord of the RP-U100 is not plugged into the AC
outlet.