The potential energy surface (PES) of H2CO has been revisited by the anharmonic downward distortion following algorithm, where an unrestricted ab initio method was employed during the automated exploration. Some structures previously reported on the PES of restricted theories were found to be open-shell species, and new local minima and first-order saddle points were discovered in high energy regions related to radical fragments which are important in high energy processes such as combustion. (C) 2008 Elsevier B. V. All rights reserved.