Somehow, my 'guest' account disappeared from my machine. I found this account very useful, so I tried to setup a 'guest' on my own. However, I cannot find any option in the Users and Groups dialogue that support the concept of delete all generated files upon exit.

What is the best way to achieve this? There is no setting in the lightdm configuration files that says 'no-guest'.

1 Answer 1


According to this article on OMG Ubuntu and this bug report on Launchpad, Ubuntu has disabled the guest sessions on 16.10 and 17.04 because of a security issue. The guest session is not properly confined and someone with physical access could gain elevated privileges.

If you are aware of the security issue and want to enable the guest account anyway, accepting the possible threat, there is an official procedure to do so:

How? By editing /etc/lightdm/lightdm.conf and entering the following:

# Manually enable guest sessions despite them not being confined
# IMPORTANT: Makes the system vulnerable to CVE-2017-8900
# https://bugs.launchpad.net/bugs/1663157
  • I would be using it to do banking etc. making sure that no key-logger is installed etc. Is there a safer way to do that? Or, would it be enough to assign the guest account a password? Jun 16, 2017 at 13:51
  • after making the change to lightdm.conf is there any way to restart lightdm without logging out?
    – kapad
    Dec 21, 2017 at 10:04

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