Hi Cubasis99999,
One more thing regarding the black instrument rack window (which you have seen with Synthmaster):
As mentioned before, something like this appears when the connection with an external instrument is lost.
If you experience this case, you can give it a try to close/reopen the instrument rack.
Additionally, relaunching Cubasis should solve the issue.
In any case, please make sure to have KV331 Audio informed about the issue.
Thanks
Lars