AU plugin not compatible with Ableton 8.4.2 after upgrade to JUCE 4.3

I’m working on an AU plugin that was working fine with my version of Ableton 8.4.2 (64 bit) until I upgraded JUCE today. When building with JUCE 4.3 and then attempting to load it into Ableton, I get the error message “This Audio Unit Plug-in is not compatible. Failed to initialize.”

Does auval https://developer.apple.com/library/content/technotes/tn2204/_index.html provide any additional information?

Thanks for your reply!

auval tells me FATAL ERROR: Initialize: result: -10868 and then some lines of *** Leaked objects detected: 2 instance(s) of class HashMap and such.

Does the fatal error have something to do with the supposed leaks? I don’t think so, because I removed the assertions in juce_LeakedObjectDetector.h for the time being and it still gives me the error.

So -10868 seems to be kAudioUnitErr_FormatNotSupported

Well that’s not very enlightening…

Are you aware of the new multibus API? If not, here is a video explaining the changes: https://www.youtube.com/watch?v=iwdMGchKT9Y. I think this may be the cause of your problems.

I wasn’t aware of the multibus API, thanks for the hint. I changed my main class as suggested here but the error still persists. I’ve generated and built a new empty project with Projucer 4.3.0 and it passes all tests. I guess I can start porting my code bit by bit into this new project and see where it fails.

Please let us know how you get on.

Sure, I will. Thanks again for your help so far.