@tjrob The .vst3 is a bundle (a folder with other files in it) but you don't need to open that folder or touch any of the files inside. Just place the .vst3 file in correct location for your OS: https://helpcenter.steinberg.de/hc/en-us/articles/115000171310-VST-plug-in-locations-on-Mac-OS-X-and-macOS