There does seem to be something unique about these particular vstsound files; the files are not listed in Library Manager under any library or any category, can’t reside on External, etc:
The question in that thread is similar to what I also see and is unanswered:
“Is there any way to move these files? They are on my space-limited boot drive and since they’re not in the Library Manager I can’t move them to a secondary drive using that utility…?”
It seems, for mysterious reasons, some of the VSTs (which may not even be sounds) are only allowed to be on the Internal, so, registering them ‘magically’ copies back to Internal if they were on External. Some of these VSTs may be from Cubase installation (and perhaps not the “Content” installation, but the app installation); but, it is impossible to know which file corresponds to which app, or even which library (VST bundle) since this information is not published in any user documentation; and difficult to know which app installed which content, since Dorico is not a Library Manager “category” (not that it should be, which might be more confusing).
Similarly, from Tonewheel Organ and Halion 7 - #8 by Dave :
The issue I have is that is is that I can’t see a way to cross check the sound file with the preset names.
The Library doesn’t show the sound file name FCP_SMT_047_HS_Tonewheel_Organ_01 and the Halion sonic 7 and Halion 7 only show preset names. … I would have thought that there would be a list which shows which program names are associated with which vstsound file. It all feels a little messy as it stands.
I agree with that. A bit messy as it stands.