Sometimes when coming back after locking the screen I am unable to unlock. The login box on the screen has a disabled password input field with the buttons also disabled.
Except for the mouse, the entire screen is frozen. Even the time in the top of the screen stops going. The only way to continue is to move to a tty (Ctrl-Alt-F1), log in and kill gnome-screensaver.
Since the time also stops going I have deduced that this seems to happen on days and times that correspond to when the cleaners are here. Because of this I speculate that they accidentally press some keys, including the enter key. This of course fails to unlock and after a certain timeout it then proceeds to freeze.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: gnome-screensaver 3.6.1-7ubuntu4
ProcVersionSignature: Ubuntu 4.4.0-22.40-generic 4.4.8
Uname: Linux 4.4.0-22-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Jun 9 08:59:15 2016
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GsettingsGnomeSession:
org.gnome.desktop.session session-name 'ubuntu'
org.gnome.desktop.session idle-delay uint32 300
InstallationDate: Installed on 2016-05-27 (12 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: gnome-screensaver
UpgradeStatus: No upgrade log present (probably fresh install)
Status changed to 'Confirmed' because the bug affects multiple users.