Could not connect to coreMIDI

Cubase hangs when loading up coreMIDI, then say ‘Could not connect to coreMIDI’.
Also, the OSX Audio MIDI Utility hangs.

I have tried removing all MIDI Drivers, yet situation the same.

Any Ideas?..

Hi and welcome,

I would say it’s on the OS side, if you can’t start even the system Audio MIDI utilities. Please, try to search on some macOS forums.

Try to run First Aid in the Disk Utility.


I was wrong. This seems to be on the driver side, now.

I can reproduce the bug even with macOS 10.13 when UR28M or UR824 (i.e. Yamaha/Steinberg Audio Devices without MIDI) drivers are installed in the system. I couldn’t reproduce it in the past and now I can reproduce it on both (10.13 and 10.14).

Could you try to install an older Yamaha/Steinberg driver for your UR28M or UR824, please?