Abstract: [Joint work with Arvin Shahbazi-Moghaddam.] We prove a singularity theorem based on the covariant entropy bound. The theorem connects singularities to quantum information, and it eliminates the assumption of noncompactness from Penrose’s 1965 theorem. A quantum extension of our theorem further eliminates the null energy condition. It can be applied to an evaporating black hole, where it leads to an interesting puzzle.