Why did OsiMIDI stop working after a Windows 11 update?

If OsiMIDI T1 or OsiMIDI Stage suddenly stopped working after a Windows 11 update, the reason may be that the update installed and enabled Windows MIDI Services.

Microsoft is gradually rolling out this new MIDI platform on Windows 11. Although it introduces important improvements to MIDI on Windows, it also changes the way MIDI devices are handled by the system, which affects compatibility with older software versions.

To address this, we have developed new versions of OsiMIDI software that are compatible with Windows MIDI Services:

  • OsiMIDI T1 2.5.1
  • OsiMIDI Stage 1.6.4

Previous versions are not compatible with this new MIDI platform, so if Windows MIDI Services is enabled on your system, you must install the latest version available on our website.

How to check whether Windows MIDI Services is enabled

Before making any changes, we recommend checking whether Windows MIDI Services is enabled on your computer.

You can verify this using Microsoft's tool here:

https://microsoft.github.io/MIDI/

If the tool confirms that Windows MIDI Services is enabled, there are two ways to solve the issues that may appear.

1. Recommended solution: update the MIDI controller driver and OsiMIDI software

In most cases, the correct solution is to make sure your MIDI controller is using one of the drivers provided by Windows MIDI Services and then install the latest version of OsiMIDI software from our website.

Step 1: Check the MIDI controller driver

Open Device Manager in Windows and locate your MIDI controller under Sound, video and game controllers. Right-click the device and select Properties to review which driver is assigned to the controller.

If the driver is one of the new Microsoft drivers listed below, it is correct:

  • USBMidi2-ACX (recommended)
  • USB Audio Device

If the MIDI controller does not work properly with one of them, try the other one. Always restart your computer after changing the assigned driver.

If your MIDI controller is using a manufacturer-specific MIDI driver, such as a Korg driver, remove it by following these steps:

  • Physically disconnect the MIDI device.
  • In Device Manager, open the View menu and select Show hidden devices.
  • Expand Sound, video and game controllers and find the grayed-out device.
  • Right-click the device and select Uninstall device.
  • If Windows asks whether you want to completely remove the driver, confirm that option.
  • Restart your computer.
  • After restarting, the device should be assigned automatically to one of Microsoft's new MIDI drivers.

If your MIDI controller is not using one of these drivers, use the Update driver option in the contextual menu and select one them. USBMidi2-ACX is recommended, but use USB Audio Device if the first one does not work properly.

If your controller is not using one of these drivers, it may not be recognized correctly by MIDI software.

When the correct driver is installed, OsiMIDI software will usually detect the controller, but previous versions will still show a connection error in the Configurator or when you click Start, because you still need to update the software to the new version compatible with Windows MIDI Services.

Step 2: Install the latest version of OsiMIDI software

Install the current version available on the OsiMIDI website.

  • OsiMIDI T1 2.5.1
  • OsiMIDI Stage 1.6.4

Previous versions are not compatible with Windows MIDI Services.

Additional benefit for T2 and T3 users

For T2 and T3 users, Windows MIDI Services also provide an additional benefit. Microsoft's new MIDI drivers support multi-client access, allowing OsiMIDI T1 and Titan Go to open the same MIDI device at the same time. This completely eliminates the startup-order issues that could occur with previous MIDI drivers.

Important note for Korg controller users

If you use a Korg controller with a proprietary Korg driver, please read this carefully:

Do not use the Korg Driver Uninstaller, or any other utility that modifies MIDI driver registry assignments or removes MIDI drivers.

Using that utility can break Windows MIDI Services and cause additional MIDI problems in Windows.

If you need to remove a proprietary Korg driver, do it through Device Manager instead, as described above.

2. Alternative option: uninstall the Windows update

If you do not want to use Windows MIDI Services yet, another option is to uninstall the Windows update that enabled it and return to the previous Windows MIDI system.