  We define a $K$-theory for pointed right derivators and show that it agrees
with Waldhausen $K$-theory in the case where the derivator arises from a good
Waldhausen category. This $K$-theory is not invariant under general
equivalences of derivators, but only under a stronger notion of equivalence
that is defined by considering a simplicial enrichment of the category of
derivators. We show that derivator $K$-theory, as originally defined, is the
best approximation to Waldhausen $K$-theory by a functor that is invariant
under equivalences of derivators.
