Keyboard issues?
If you have a casio keyboard and you are trying to connect it, don't use USB! Mac users will not have ANY
luck😟. Just use a headphone converter jack and plug it into the headphone out port on your keyboard, then
plug in the smaller end into the mic in port on your mac. Now make sure your microphone is set to line out and play away!
MacBook, OS X El Capitan (10.11.6), Keyboard Fixing