Before installing v16.01.2020, use the "Uninstall" feature in Waves Central or manually delete the Waves folder in /Library/Application Support . Conflicts between V9/V10 and V11 are the #1 cause of "Plugin not found" errors.
macOS 10.12.6 (Sierra) through 10.15 (Catalina).
Waves is the industry standard for mixing and mastering, but their update cycle is aggressive. Version 11 was a milestone because it introduced full compatibility with macOS Catalina (the first 64-bit-only OS) and provided the foundation for the modern Waves Central interface.
macOS security (Gatekeeper) often blocks older plugin installers. If the installer fails, go to System Settings > Security & Privacy to allow the app to run.