  Arveson's hyperrigidity conjecture predicts that if the non-commutative
Choquet boundary of a separable operator system $\mathcal{S}$ is the entire
spectrum of its generated C*-algebra $\mathcal{B}$ then $\mathcal{S}$ is
hyperrigid in $\mathcal{B}$. We provide a counterexample to the conjecture with
a C*-algebra $\mathcal{B}$ of type I generated by a single operator.
