If I login as the admin, I can see User profile link in navigation menu; but, if I log in as a normal user, it desappears. So it's impossible for a user to modify his password, for example.
I gave authenticated user the permission to see user profile.

If I log as the admin and go in menu administration, i find "User profile" and just next: "locked".
What does it mean? It's the only "locked" link I have.