VST3 MIDI Plugins Won't Load in Ableton Live

I’m building a plugin that generates MIDI and I’m having trouble loading the VST3 build in Ableton Live. Same goes for the ArpeggiatorPlugin demo that comes with Juce 5.4.5:

This happens on both Windows and Mac (Mojave) in the latest Ableton Live version (10.1.5). Other Juce VST3 plugins load just fine (e.g. the GainPlugin), and the VST2 version of my own plugin works flawlessly.

Does anyone know what the problem is here?


Thanks, but that’s not the same problem. I get an error when I try to put the plugin on any track. Ableton just won’t instantiate it.

OK, I found a solution. Checking “plugin is a synth” in the Projucer and adding an audio output to the processor does the trick.

This will work for me (I was planning to output audio anyway) but surely it must be possible to do MIDI only VST3 plugins?

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Is there any additional information on this? I’m having the exact same issue, but checking “plugin is a synth” isn’t working for me. The plugin will load in the JUCE audio host, but nothing else. I’ve tried Ableton and FL Studio, on both Mac and Windows, after compiling in Xcode and VS2019, respectively. I keep getting the same error message listed at the top of this thread.

I haven’t really investigated any further, I’m afraid.

How are the output buses of your plugin set up? IIRC it quite possible to load up a VST3 with no outputs in the AudioPluginHost, but not in Ableton.

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The thing with Ableton VST3 is they don’t allow to have empty input bus.
I’ve logged it with Ableton (and you can reference to it):

I guess it might be the same with FL.

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Yup, that appears to be the problem. I just downloaded Reaper and my VST opens with no issues. Thanks so very much for pointing this out. This was slowly driving me insane.

Thanks for clearing that up… everything makes more sense now :slight_smile:

Hmm… it seems that Ableton Live will load other VST3 plugins with no audio inputs just fine. If I load up any of the Arturia V Collection VST3 plugins in the AudioPluginHost, I see they have no audio input busses - and they work just fine in Live.

I think this must be a JUCE problem somehow?

I’m able to make it work if I don’t check the box for MIDI Effect Plugin. I haven’t checked to see what’s different about the resulting code with this box checked, but the problem could be related to this.

Thanks, works for me too.

I guess I need to spend some time studying the generated code too… those properties are not very intuitive :frowning: