Hi, I am not getting an error message, it took me 7 hours yesterday to, they call it copy now, not transfer to transfer my 7700 songs from MacBook Pro to iPhone 12 mini. I did this because in the car on CarPlay, I got a message that said you have to cellular connection and all my music was in my library in the cloud. This week I am going to work on seeing if they are letting me match the first as Phil suggested I look.
I am also driving from canon city CO to Ruidoso and there will be plenty of dead cell areas, so I will see if Apple will let me play my own music without a cellular connection.
But don’t you think a 7 hour transfer rate over a usb c to lightening cable is just a little slow? To me it was painful.