A quick update.
I’ve spent some more time investigating this and I’m 99% sure this is an Omnisphere issue. It only happens on Windows 7 and it only happens if you open/close the plugin UI before unloading or deleting it.
Yesterday I sent a screen cast of a debug session to Spectrasonics detailing the problem and they’ve confirmed they can reproduce it, seem to agree on the problem and are looking into it.
I’ve tried a couple of things to work around it in Cantabile but no luck so I think we need to wait for a fix in the plugin itself.
Also, this problem isn’t exclusive to Cantabile. Forte also crashes and VstHost starts logging thousands of access violation exceptions but (dangerously) suppresses them.
Stay tuned…
Brad