What's the difference between these?

Wondering what if anything is the difference between these two plugin files other than one being .vst and the other an audio unit file.

/Library/Audio/Plug-Ins/Components/HALion Symphonic Orchestra.component
/Library/Audio/Plug-Ins/VST3/Steinberg/Symphonic Orchestra.vst3

I’m not sure if the first is an audio unit, but in any case I wouldn’t ignore the Symphonic Orchestra plugin. You should use Halion Sonic SE, which is much more recent than this plugin and will load all the HALion Symphonic Orchestra content.

Not 100% on what you’re telling me…

So the HALion Symphonic Orchestra.component is safe to delete as far as Dorico is concerned?

I just did a complete reinstall of Dorico Pro 2 yesterday on a new computer and the Halion Sonic SE plugin was not installed. If this is the most recent, why didn’t the installer add it to the system? Should the second plugin shown in my original message be replaced by the Halion Sonic SE plugin?

I wouldn’t delete it. If you did then running installers or updaters in the future may just put it back. If HSSE isn’t installed then ensure that all the playback components have been downloaded from the Steinberg Download Assistant. It should install Halion Sonic SE as well as Symphonic Orchestra.