I hope this will help some folks who are experiencing anomalies on their Windows 11 computers.

Microsoft has rolled out an update that is supposed to provide updated MIDI support for Windows (to include the MIDI 2.0 spec). However, apparently update 25H2 KB5079473 causes a lot of problems with several DAW's that just hang on scanning for MIDI ports and then just lock up. I asked Gemini (AI) what the plan is and received the following response:

Quote
Microsoft is currently targeting the fourth week of March 2026 for a formal bug fix to resolve the MIDI port and "lockout" issues introduced with recent Windows updates. The problems stem from the rollout of a new Windows MIDI Services architecture (which includes native MIDI 2.0 support). This new stack has caused behavioral incompatibilities with older MIDI 1.0 applications and drivers, particularly those from brands like M-Audio, AKAI, and Korg.

Current Known Issues
Port Disappearance: MIDI ports may not appear in DAWs or configuration tools.
Driver Lockouts: Certain third-party drivers (e.g., inMusic-branded) can cause the MIDI service to hang or lock up.
Enumeration Errors: New devices are sometimes assigned to higher port entries (midi10+) that older software cannot recognize SysEx Timing: Some applications experience timing issues when sending large blocks of System Exclusive (SysEx) data.

Official Workarounds
Until the official patch is released, Microsoft and hardware manufacturers suggest the following temporary solutions:
Restart the MIDI Service: Open Services (via Windows Tools), find Windows MIDI Service, and click Stop then Start. This often restores hidden ports temporarily.
Uninstall Problematic Drivers: For Korg users, it is recommended to uninstall the KORG USB-MIDI Driver and use the native Windows MIDI Service instead.
Power/Connection Sequence: Plug in your MIDI devices before launching your DAW, or leave them connected and perform a full system reboot to force proper enumeration.
Roll Back the Update: Many users have found stability by uninstalling the KB5079473 update until the fix is deployed.

Microsoft and the major DAW vendors are aware that the 25H2 update (KB5079473) is causing severe startup lockups for applications like Steinberg Cubase 15 and Fender Studio Pro 8. The hang occurs specifically during the "Initializing: All MIDI Inputs" phase because the new Windows MIDI Services architecture is failing to communicate with certain third-party drivers.

Fix Timeline and Vendor Status
Microsoft: A formal cumulative update addressing virtual port and service-level lockups is currently scheduled for the end of April 2026. A smaller "preview" fix for virtual ports is already circulating in developer communities.
Steinberg: They have officially acknowledged that Cubase 15 hangs on startup due to the wdmaud2.drv driver introduced with this update. They are working directly with Microsoft, but currently recommend a system rollback as the only reliable fix.
Fender/PreSonus: For Fender Studio Pro 8, some users have found success by installing an older version of "Universal Control" or applying the "voluntary" KB5074109 update if it appears in your Windows Update history.

John

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