I have a user running 10.5.8 on a 1.5 ghz G4 mac mini. It's set to require a password to unlock the screen saver. She will be working, putting in her password each time the screen goes to sleep, and then all of a sudden she goes to wake up again and it refuses the password. The only way that I've been able to fix it is to use the administrator username/password, and to reboot.

Perhaps related, or completely irrelevant, she is a mobile user, and the sync that happens when she logs in or out has suddenly started taking hours.

Any clues?