  We discuss the geometric engineering of SO/Sp gauge theories with symmetric
or antisymmetric tensor matter and show that the `mysterious' rank zero gauge
group factors observed by a few authors can be traced back to the effects of an
orientifold which survives the geometric transition. By mapping the Konishi
constraints of such models to those of the U(N) theory with adjoint matter, we
show that the required shifts in the ranks of the unbroken gauge group
components is due to the flux contribution of the orientifold after the
transition.
