Tried: reimport works. At least it seems: no error nor "done" window.
And VM works like before: boots, can be used etc.
And it continues to fail if I try "clone".
I also tried to clone it with a trial of 17.0.2, thinking it could be a bug of my old 14 version.
But it says the same: "Cloning failed: one of the parameters supplied is invalid"