Peculiar MIDI program change problem on VSTs with loopback MIDI (win10)

I have been trying to send /midiprgm change to different VSTs in Ableton via loopMIDI software.

The problem is that only some of the VSTs are responding to these changes and most of my plugins are not.

What is super weird that almost all of my free or open source plugins work with the program change (Dexed, Mausynth, Ravegenerator) but none of my commercial VSTs are working (FM8, Iris 2, U-he Synths, Omnisphere).

Now I’m pretty puzzled why is it like that, so I was wondering if there is any Win10 Ableton Live 11 (with loopMIDI) users that have any of the VSTs I mentioned that could try out if it’s the same for you?

Scott has been helping with this problem on Mac, which was working correctly, so I’m just trying to troubleshoot where the problem could be. I also made a Reaper test that replicated the problem, so it should’t be Ableton.

Here is a simple code to test:

\type, \midi,
\midiout,MIDIOut.newByName("loopMIDI Port", "loopMIDI Port", 2),
\midicmd, \program,
	\progNum, Pwhite(0,20),


A useful test would be: If you send the program change from software other than SC, does the plugin respond?

(Differential testing: Isolate variables by changing one thing at a time. You’ve swapped out the DAW and found that didn’t change the result – also try swapping out the source of the messages.)


Yea, I didn’t specify, but my Reaper test was already that. Scott/scztt told me that in the MIDI editing window of Reaper, you can open this command list for inputting CC and MIDI Program changes.

When I put FM8 there for the PC, it open a windows which has a drop menu for programs that is filled with (disabled).

If I do the same for Dexed, the same drop menu fills in correctly with the different patch names.

Very weird. But maybe I need to a fill a bug report for scztt to work on it at Native xD