<div dir="ltr">In both cases the log is showing the authentication failed: [+5.14s] DEBUG: Session 15571 authentication complete with return value 7: Authentication failure [+57.17s] DEBUG: Session 15831 authentication complete with return value 7: Authentication failure </div><div class="gmail_extra"> <div class="gmail_quote">On 27 December 2012 12:07, David Edmundson <<a href="mailto:david@davidedmundson.co.uk" target="_blank">david@davidedmundson.co.uk</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Log for user foo which should have no password having run "sudo gpasswd foo nopasswdlogin" before. [+5.13s] DEBUG: Greeter start authentication for foo [+5.13s] DEBUG: Started session 15571 with service 'lightdm', username 'foo' [+5.14s] DEBUG: Session 15571 authentication complete with return value 7: Authentication failure [+5.14s] DEBUG: Authenticate result for user foo: Authentication failure [+5.14s] DEBUG: Session 15571 exited with return value 1 It's definitely doing something different, because for a regular user, I get a prompt, and a 3 second delay before authentication completes. [+54.74s] DEBUG: Greeter start authentication for david [+54.74s] DEBUG: Started session 15831 with service 'lightdm', username 'david' [+54.77s] DEBUG: Session 15831 got 1 message(s) from PAM [+54.77s] DEBUG: Prompt greeter with 1 message(s) [+54.77s] DEBUG: Continue authentication [+57.17s] DEBUG: Session 15831 authentication complete with return value 7: Authentication failure [+57.17s] DEBUG: Authenticate result for user david: Authentication failure [+57.17s] DEBUG: Session 15831 exited with return value 1 Dave </blockquote></div> </div>