> Make sure that "sudo -u USER /bin/pwd" prints > something reasonable rather than, say, a "permission denied" error. Hi, Running that command prints out the current working directory correctly, as does logging in as the user and running "/bin/pwd" and "echo $PWD". However, I think I've found the cause of the problem, even if I have no idea why it would cause this - when the new user runs "export", no PATH shows up. If I run "echo $PATH" it shows up as I'd expect, and when I do "export PATH" suddenly gcc can #include <stddef.h> just fine. There must be some subtlety I'm not aware of... I don't suppose you could shed any light on what's going on here? Thanks, John G