Hi! The issue is the XMA hardware, which can only be used by one of the tools. If Unity's audio toolset is enabled, it uses the XMA hardware and Wwise can't initialize. You can disable Wwise's XMA usage by setting AkPlatformInitSettings.uMaxXMAVoices to 0 (it is also visible in the Init Setting property editor). But, obviously, this will prevent XMA usage in your audio design, you'll have to use Vorbis, ADPCM or Opus. Otherwise, you can ask Unity for a toggle to disable XMA initialization (hint, they refused in the past).