Hi again Paul
When I go into Logic Pro X Plug-In Manager, Vienna does not appear as a manufacturer. If it did, then I could re-scan and get it to work. It is clear that Logic is not recognising Vienna and when I go into Macintosh HD/Library/Audio/Plug-ins/Components, a VST file is there but it is empty. Not sure if this helps you solve the problem or not but 'ingers crossed' that it does
best
kevin