Prevent Ubuntu from asking a password after resuming from Hibernate or Suspend
When you close the lid of your laptop and Ubuntu is running, the computer goes into Suspend mode. Same goes for chosing Hibernate from the shutdown menu, when the laptop goes into deep sleep and consumes less power. When resuming from these two states, Ubuntu will ask you for your password. If you’d like to get rid of this password field, you need to launch gconf-editor and navigate to apps > gnome-power-manager > lock. There you’ll find a checkbox for hibernate and one for suspend. Uncheck these and close the Configuration Editor. Next time you resume from Suspend and Hibernate, you won’t be prompted for a password.
You can still manually lock your screen before closing the lid by using Ctrl+Alt+L.