I think setgid() will set real to the _saved_ GID, but not the _effective_ GID. Try setregid() and see if it behaves any better. Print its status, and the errno from exec. Bruce -- Pixar Animation Studios: Reality is not our business. Pixar's "Toy Story" $184,849,036 domestic, $117.5M overseas and counting. That makes it number 21 in box office figures of all films ever released.