My oxygen 25 midi keyboard is 'compliant with el capitan' according to the m-audio website, but I noticed none of my DAWs could establish a connection or receive a midi signal.

To prove no signal received, I downloaded midi monitor after following instructions here:

Apple Midi Test

Launching MIDI MONITOR, I get the following message

MIDI Monitor could not make a connection to its MIDI driver. To fix the problem, quit all MIDI applications (including this one) and launch them again.

For now, MIDI Monitor will not be able to spy on the output of other MIDI applications, but all other features will still work.

This leads me to believe the problem is with my OS upgrade rather than my hardware. I upgraded to 10.11.2 with the hopes that it may fix the issue, but it was to no avail.

What can I do to restore midi function in my macbook pro? This was working prior to el capitan upgrade.

2 Answers 2


We had the same midi issue after upgrading to El Capitan 11.10.2. After working many hours with Apple's support team, they finally suggested we revert back to Yosemite. Weak sauce or apple sauce, you decide :)

  • :( were you getting the same error message? Jan 13, 2016 at 18:40

Instead of downgrading the OS I upgraded my midi controller. Not particularly relevant, but I switched from m-audo to akai.

This fixed the issue, even though the previous device was listed as compliant on the MFs website. I made sure the new device was also listed as USB compliant.

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