If a connected MIDI device isn’t shown in Audio MIDI Setup on Mac
When you open Audio MIDI Setup on your Mac, a MIDI interface connected to the USB port is usually detected automatically and shown in MIDI Studio. If it isn’t, you may need to rescan the MIDI connection for the device. If you connect another MIDI device to the MIDI interface, you need to set that device up.
In the Audio MIDI Setup app on your Mac, choose Window > Show MIDI Studio.
In the MIDI Studio window, click the Rescan MIDI button .
If the device still doesn’t appear, make sure it’s properly connected to your Mac, that it’s turned on, and that you installed any software required by the manufacturer.
If the device is connected to the MIDI interface on your Mac, set up the MIDI device.
If you delete a MIDI interface and then decide you want to continue using it, you need to rescan the MIDI connection to see the device in Audio MIDI Setup. If you delete a MIDI device that’s connected to the MIDI interface, you must set up the MIDI device again.