How to enable guest account automatic login?

Solution 1:

Edit /etc/lightdm/lightdm.conf with your favourite editor like gksu gedit /etc/lightdm/lightdm.conf and under the section [SeatDefaults] add

allow-guest=true  
autologin-guest=true  
autologin-user-timeout=0  
autologin-session=lightdm-autologin  
user-session=ubuntu

Solution 2:

For both Ubuntu 14.10 and Ubuntu 15.10 this is what worked for me:

sudo nano /etc/lightdm/lightdm.conf

with the following content

[SeatDefaults]
autologin-guest=true

What did not work for me under Ubuntu 14.10 (Note: this was not tried under Ubuntu 15.10)...

1. Creating the 50-autoguest.conf file in /usr/share/lightdm/lightdm.conf.d/
2. Creating the 50-autoguest.conf file in /etc/lightdm/lightdm.conf.d/
3. Having the setting allow-guest=true in the settings file (that disabled Guest session altogether).

According to the LightDM wiki entry, the right place to put such modifications is in

/etc/lightdm/lightdm.conf
/etc/lightdm/lightdm.conf.d/*

The following path is for the system-provided configuration only

/usr/share/lightdm/lightdm.conf.d/

Source: https://wiki.ubuntu.com/LightDM

The way I solved this was 'brute force'. I knew that I could set an auto-login using a regular account in Ubuntu 14.10 so I did that in Settings. Then I looked in the three locations I knew of where the auto-login preference was stored and, voila, the file /etc/lightdm/lightdm.conf was created with a single entry for the account that was subject to auto login. Figuring that less is more I commented out the entry (prefixed #) and added only autologin-guest=true and it worked!

PS nano is my preferred command-line text editor. Its simple to use. That said, use whatever is your preferred text editor, e.g. gksu gedit if you prefer a GUI text editor.

Solution 3:

The lightdm config file location has changed in Ubuntu 14.04. To accomplish the same you need to create a new file /usr/share/lightdm/lightdm.conf.d/50-auto-guest.conf, for example by running

gksu gedit /usr/share/lightdm/lightdm.conf.d/50-auto-guest.conf

and putting in this content:

[SeatDefaults]
allow-guest=true  
autologin-guest=true  
autologin-user-timeout=0  
autologin-session=lightdm-autologin  
user-session=ubuntu