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ned3000's avatar
ned3000
Copper Contributor
Feb 21, 2026

MIDI sysex message transmit fails after installing Security Update KB5077181

In the widely used MIDI application MIDI OX, I can no longer transmit MIDI sysex messages to a MIDI output port. Connecting a MIDI input in the app to a MIDI output echoes MIDI channel messages normally. Sysex messages do not appear in the output window and are not sent to the MIDI output port. Also, attempting to send a sysex message from within the app results in the error message "SysEx: No Buffers Available".

I was able to repoduce this with two USB MIDI interfaces: M-Audio Midisport 4x4, and MOTU Midi Express 128.

Uninstalling Security Update KB5077181 restores expected functionality.

This is on Windows 11 Pro.

LInk to my feedback hub report on this issue: 

https://aka.ms/AAzwx9y

MIDI

1 Reply

  • JBarrol's avatar
    JBarrol
    Copper Contributor
    Feb 23, 2026

    Microsoft may release a fix or workaround in subsequent updates addressing this compatibility problem. Ensure your Windows is current, and monitor Windows Update for patches.