A non-radial non-adiabatic linear stability analysis of stellar models with initial masses on the zero-age main sequence (ZAMS) between 20 and 80 M⊙ is presented. Two groups of dynamical mode-coupling instabilities are identified. We examine the influence of the treatment of convection on these instabilities, as well as their dependence on the stellar mass and the harmonic degree l of the perturbation. The instabilities are discussed within the context of a recently proposed model for strange-mode instabilities.