Enable Guest Logins in Ubuntu 18.04 Bionic

By default Ubuntu 18.04 ( non-Groovix ) no longer offers guest logins. But you can enable guest logins by switching the display manager from gdm3 to lightdm and enabling guest logins with the following steps.

NOTE: due to bug CVE-2017-8900 https://bugs.launchpad.net/bugs/1663157 guest accounts are not as restricted as they were in 16.04, the most practical difference is that some applications can read other users files ( or even write, it depends on your file permissions like any normal multiuser system ) . Most applications in Xubuntu 18.04 seem to be restricted but until that bug is resolved there are no guarantees, so only use this feature if you understand the security implications.

• sudo apt install lightdm ; # be sure to choose lightdm as the default greeter
• sudo gedit /usr/share/lightdm/lightdm.conf.d/50-disable-guest.conf ; #change it to: allow-guest=true
• Reboot the computer ( through the gui or shutdown -r now )