Why do I get getting this message? I’m trying to reload everything from a dead computer to my new one.
A screenshot might help. Also describe what you’re doing when the message appears.
What system are you migrating from / to and what version of Cubase from / to.
That looks like the kind of message you would get when opening a project, not Cubase itself.
In that case it would indicate a Midi port that was assigned in the project but doesn’t exist any more. Has your Midi port configuration changed from your old machine to the new one?