1. Never allow any Temporary User without a password to gain Access Control of your computer!
FIRST Make a policy to prevent the single user guest from making system wide changes
open text editor gksu gedit /etc/polkit-1/localauthority/50-local.d/10-desktop-policy.pkla
insert text
[guest-policy]
Identity=unix-user:guest
Action=*
ResultAny=no
ResultInactive=no
ResultActive=no
2. open terminal and start typing
sudo addgroup --system --quiet --gid 126 guest
sudo useradd -c Guest,,, -d /tmp/guest-home.UBUNTU -m -s /bin/bash -g guest guest
sudo usermod --uid 117 --gid 126 guest
to create blank password for this account:
sudo usermod --password U6aMy0wojraho guest
to create Not asked for password on login for this account:
sudo usermod --groups nopasswdlogin guest
Edit /etc/gdm/gdm.schemas
type:
gksu gedit /etc/gdm/gdm.schemas
and add guest to greeter/Include
default
<schema>
<key>greeter/Include</key>
<signature>s</signature>
<default>guest</default>
</schema>
now sudo restart gdm
NOTE: you will no longer be abel login to guest sessions from user accounts
this is the new guest session
and you will only be able to login from login screen any changes to this account will remain on logout until the computer restarts.
to restore open terminal and type:
sudo userdel guest
then sudo restart gdm
to copy your settings for guest session
sudo cp -R ~/.gconf/desktop /etc/gconf/gconf.xml.system/
sudo cp -R ~/.gconf/apps /etc/gconf/gconf.xml.system/
sudo chmod 777 -R /etc/gconf/gconf.xml.system/desktop
sudo chmod 777 -R /etc/gconf/gconf.xml.system/apps