Anyone knows about this compile time error?

Hello I recompiled a project after a long time and i am getting this error

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_CABTLEMIDIWindowController", referenced from:
      objc-class-ref in include_juce_audio_utils.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Looks like that’s a function from CoreAudioKit which is available on OS 10.11+. I haven’t encountered this error before, but here’s some stuff you could try:

  • Check that your project links against that framework (Projucer should do this automatically, so if you haven’t regenerated the project files in a while then definitely do that).
  • Check your deployment target is set to 10.11 or later.