PlanetZ forums - scopeusers.com

Is that the message that says "no more connections possible between card # and card #?

It will specifically throw up an error that says the stdm cable is probably not present as half of the string given. I don't recall the exact wording, it might include what you're referencing as well.

The easy way to find out is to remove the cables, boot, and load scope. The default project is often enough to give the error, if not the first (moderately heavy) device I load. And it's always when I forget to put them back on, though in the past I saw it with dodgy cables as well.