In this paper, the influence of pre-existing crystalline damage, such as cracked or broken cells or soldering failures, as they are frequently observed in operating photovoltaic (PV) plants, on the degradation behavior of mono- and polycrystalline silicon PV modules is investigated. In particular, it is analyzed if and to what extent pre-damage introduced prior to lamination propagates upon stress exposure. Therefore, the pre-damaged modules are exposed to various accelerated aging conditions in order to analyze the impact of the pre-damage on the degradation behavior under the respective aging scenario. In order to separate the influence of the pre-damage from composition-induced influences, the choice of materials used in the modules is varied. These investigations reveal that none of the accelerated aging tests causes any change in the pre-existing damage. In fact, the degradation behavior and rate rather depended on the choice of the module components than on the nature of the pre-damage. Finally, these results are compared with indoor and outdoor results obtained from other studies.