I can't enable lock screen mode in my laptop and also in my PC. I went to system setting > screen > lock Ctrl+Alt+L : Nothing happens! the shortcut is there but not works !
sudo apt-get --reinstall install gnome-screensaver : Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: dassault-systemes-draftsight:i386 : Depends: sendmail:i386 but it is not installable PreDepends: libdirectfb-extra:i386 (>= 1.2.7-2) but it is not going to be installed PreDepends: libxcb-render-util0:i386 (>= 0.3.6-1) but it is not installable E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).