NOTE: If you are using High Sierra you might need to restart your Mac before you can use the AU version of your plugins. This is a common issue with High Sierra (macOS 10.13.x). If you aren’t using High Sierra, follow the instructions below.
1 – Check The Plugin Manager
Firstly, look at the plugin manager. Check if the plugin is validated or not. Please watch the quick guide video about the Audio Unit validation.
2 – Clear Audio Unit Cache
If you can’t see the plugin name in the plugin manager list; you need to clear the audio unit cache. Please watch the quick guide video about the Clearing Audio Unit Cache.