NB: beware of this bug!
Symptoms: lock screen takes very long (ie, a few seconds) to process username+password, returns “authentication error”, and becomes impossible to log in and unlock the screen again, with any user.
Also, /var/log/syslog
shows:
Failed to add watch on /run/systemd/ask-password: No space left on device
Solution: see bugs.launchpad.net and follow link in answer #2: support.code42.com. This worked for me.
Solution: install gnome-shell
and gnome-shell-extension-autohidetopbar
(may have dependencies), then configure
running gnome-shell-extension-prefs
.
Solution?