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M-Audio MIDISPORT USB 64-bit MIDI device driver for MacOS v10.14+ (Mojave to Ventura)


This project provides an open source MacOS v10.14 - v13.4 (Mojave to Monterey) compatible CoreMIDI 64 bit device driver for M-Audio's MIDISPORT range of USB MIDI interfaces. This driver supports the following devices:

  • Oxygen 8 Keyboard (with extra firmware installed)
  • Radium 49/61

Other devices which are compatible may also work, although presently, these are the only ones which have been tested or reported to work. See the disclaimer below before testing this software on any device not listed above.


I originally wrote the first MacOS X version of the MIDISPORT device driver back in 2000 and donated it to M-Audio (then named MIDIMan), as part of a start-up project (tomandandy music inc.) that needed a MIDI device driver running on what was then a pre-release version of MacOS X. M-Audio took the code and updated it many times without giving me back their updated source code. M-Audio now seem to have abandoned the hardware and no longer support their version of the driver since 2009, as their newer devices do not use that driver. With the move by Apple to MacOS v10.14 and onwards to no longer support 32 bit drivers, I have modified and updated my original code that was donated, to now compile as 64 bit versions on these latest MacOS versions, so MIDISPORT owners can continue to support and operate their hardware.

Necessary Disclaimer:

This project has no support from M-Audio, and M-Audio is in no way responsible for this code. In addition, any authors listed in this code are not responsible for the fitness and suitability of purpose, freedom from defects, or behaviour of this software. There is no warranty for this code. It is essential to understand that any software interacting with a piece of hardware can potentially damage it. You therefore use this software at your own risk, and are solely responsible for deciding it's fitness to your purpose. See the LICENSE.txt file for full license and warranty declarations.

MIDISPORT is a trademark, and MIDIMAN is a registered trademark, of the M-Audio and/or MIDIMAN companies.

Project Structure

The project consists of two parts:

  1. The MacOS X CoreMIDI device driver itself, consisting of a modified version of Apple's publicly available (and now very old) MIDI device driver example code.

  2. A firmware downloader running as a launchd daemon, which downloads the firmware to transmit to, and receive from, MIDI and USB ports on the EZ-USB 8051 compatible microcontroller within the MIDISPORT devices.

MacOS X CoreMIDI Device Driver

The MacOS X CoreMIDI device driver is a modified version of Apple's publicly available (and now very old) CoreMIDI device driver example code. This was adapted for the MIDISPORT. All technical details of the MIDISPORT devices within the driver are also publicly available from the open source Linux version of the MIDISPORT driver, together with publicly available Linux and MacOS example code for downloading firmware for the EZ-USB microcontroller inside the MIDISPORT devices.

Currently the code has been tested on MacOS 10.14, 10.15, and v11.7.2, v12.6.2.


In order to avoid distributing any M-Audio supplied code, or infringe on NDAs, none of the MIDISPORT firmware is distributed as part of this project. The firmware downloader code reads Intel Hex format versions of firmware files that were publicly distributed by M-Audio as part of their Linux driver effort. Users will therefore need to download those files to their Mac and save them into the appropriate folder location for the firmware downloader to find them. However the driver installation script will perform this downloading as part of the installation of the driver.

Not all firmware for every MIDISPORT device M-Audio produced is distributed with the Linux driver. Support is currently missing for some of the later models which used different firmware. Those firmware files are distributed as part of the download for M-Audio's last 32 bit driver v3.5.3. If the .dmg file for that driver is placed in ~/Downloads, this project's installer will also install the firmware files from that old .dmg file.

Installation instructions

  1. Make sure you first remove the old M-Audio MIDI device driver from your system before installing this driver. Ideally use their M-Audio USB MIDI which is part of their DMG file for their installer. However, that won't run on Catalina/Big Sur as it's a 32 bit app. In that case, you will need to manually remove:
  • Their driver from /Library/Audio/MIDI Drivers/M-Audio USB Support.plugin
  • Their firmware downloaders from /Library/Extensions/M-AudioUSBMIDISupport.kext and /System/Library/Extensions/M-AudioUSBMIDISupport.kext.
  • Their launch daemon config from /Library/LaunchDaemons/com.m-audio.usb.firmwareloader.plist
  • Their firmware from /Library/StartupItems/M-Audio Firmware Loader/
  1. If you need to install firmware for devices other than the original MIDISPORTs listed above (for example, anniversary editions, Oxygen 8 and similar devices), download the M-Audio v3.5.3 DMG file now archived at, and place into your ~/Downloads folder. The installer will look for the DMG file there.

  2. If you are attempting to install on MacOS 10, the M-Audio DMG file extractor now requires Python v3, which was not installed as standard on that version of the operating system. You therefore need to have Python 3 installed in a location which is accessible to the installer, i.e. /usr/local/bin. For MacOS 11 and greater, Python v3 is installed by default. The easiest method to check if Python v3 is already installed is to launch and run which python3 which will report its location if it's on your machine.

  3. Download the package MIDISPORT.pkg.

  4. Double-Click the .pkg package, and follow the standard installation operation to install the plugin. When prompted for authorization to install the plugin, enter an administrator's password. Note that installer will attempt to download the firmware files, so you need to be connected to the Internet. The installer should place:

  • The plugin into /Library/Audio/MIDI Drivers/MIDISPORT.plugin
  • The firmware downloader into /usr/local/libexec/MIDISPORTFirmwareDownloader
  • A launchd configuration file into /Library/LaunchDaemons/
  • The firmware files into /usr/local/etc/midisport_firmware/
  1. You will need to reboot the operating system in order to launch the MIDISPORTFirmwareDownloader utility which will wait for MIDISPORT devices to be plugged into the USB bus.

  2. Connect the MIDISPORT device to the USB chain. If the device and the firmware files can be found, the firmware for the MIDISPORT will be downloaded which will be indicated by its LED labelled "USB" pulsing.

  3. Open /Applications/Utilities/Audio MIDI and select the MIDI Studio window of the app. You should see the MIDISPORT MIDI interface device appear, and you can then define MIDI devices and connect them to the MIDISPORT interface device in the standard operation of the utility application. Note that if you have run the M-Audio driver in the past, the previous MIDI interfaces will still appear and any MIDI devices connected to them will remain. You will need to remove those connections and reconnect the MIDI devices to the new available MIDISPORT interface.

Building from Source

The package .pkg file above will fulfill musicians requirements. If however, you want to develop the code, the entire package is compiled and built by running:

    xcodebuild -project MIDISPORT.xcodeproj -target Package -configuration Deployment install

from the command line. This will compile both the firmware downloader and the MIDI driver plugin, and produce the installable package. The package name will include the version number. To increment that version number, the following files need to be changed:

  • The CURRENT_PROJECT_VERSION value for the Package target in the MIDISPORT.xcodeproj/project.pbxproj XCode project file.
  • The value of CFBundleShortVersionString in MIDISPORT/Info-MIDISPORT.plist.
  • Localised (English only, currently) entries in MIDISPORT/en.lproj/InfoPlist.strings.