Information
GNOME Desktop Manager can make the screen lock automatically whenever the user is idle for some amount of time.
Setting a lock-out value reduces the window of opportunity for unauthorized user access to another user's session that has been left unattended.
Solution
Run the following command to set lock-delay to 5 seconds or less: enable screen locks when the user is idle:
# gsettings set org.cinnamon.desktop.screensaver lock-delay <N>
Example:
# gsettings set org.cinnamon.desktop.screensaver lock-delay 5
Run the following command to set idle-delay to 900 seconds (15 minutes) or less and not 0 (disabled):
# gsettings set org.cinnamon.desktop.session idle-delay <N>
Example:
# gsettings set org.cinnamon.desktop.session idle-delay 900
Note: Users must log out and back in again before the system-wide settings take effect.