Forum Discussion
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
5 Replies
The issue you're experiencing with MIDI OX — where SysEx messages are not transmitted and you see "SysEx: No Buffers Available" — is a common problem related to buffer management or MIDI driver conflicts.
Your issue with MIDI OX not transmitting SysEx messages and showing the "SysEx: No Buffers Available" error after installing Security Update KB5077181 suggests a compatibility or driver buffer management problem introduced by that update.
The issue you're experiencing with MIDI OX not transmitting SysEx messages after installing Security Update KB5077181 on Windows 11 Pro appears to be related to a change in how the operating system handles MIDI buffers and device access permissions. The fact that uninstalling this update restores normal functionality suggests that the update may have introduced restrictions or altered driver behaviors affecting MIDI SysEx transmission.
The KB5077181 update appears to interfere with MIDI SysEx transmission in applications like MIDI-OX. Error messages such as "SysEx: No Buffers Available" indicate problems with buffer allocation or driver communication. The problem affects multiple USB MIDI interfaces, confirming it's not device-specific.
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.
