Hi-
It looks like you are using the Octavox AU on OSX, but VST on Windows, is that correct? It doesn't look like you have the Octavox VST installed on the OSX side, so my guess is that Studio One is not able to match the plug-in between the two formats when going between Windows and OSX. I'd make sure you are using the Octavox VST on the OSX side.
If my guess is correct, on OSX you can save your old settings from the AU as a preset, change to the Octavox VST, and then load your settings from that preset.
Let me know if this helps out, if not we can continue to troubleshoot.
Best,
Tom
