How to disable guest / guest session in Ubuntu

Ubuntu offers its users a wide range of changes designed to improve the way it behaves and adapt it to the user's preferences. From this point of view, if we were to compare it with Windows 7 or 10, Ubuntu is much more permissive, incomparable, we could say.

Ubuntu, according to the factory settings, allows the existence of a user account but also a guest account. This feature is not only available on Ubuntu, but also on Windows or other GNU / Linux distributions.

The differences between the two types of accounts, guest and default, are major. If in order to log in to the main account you need a username and password, and all the work you do will be kept after restart or shutdown, in a completely different way the situation is on the guest account. It does not require the introduction of a username or password, activating at the user's request and allowing the use of the computer, which is true, we are talking about a limited use, by anyone who has access to the computer. If in the first version, after the restart, the user could find a fixed job where he saved it, but also the changes brought to the system, in the case of the guest account, this information is lost after closing / restarting. Basically, everything you did, if you accessed this session, is lost.

Due to the fact that Ubuntu allows the logging, in theory, of anyone who has access to our computer, we recommend, for security reasons, disabling this type of session. Although it can be used restrictively and incompletely, the guest account can put you in unpleasant situations. Guided by the principle "better prevent than treat subsequent wounds", we suggest disabling it. In this sense, Ubuntu developers offer this way, which can be put into practice through the Terminal.

This procedure is tested for Ubuntu 14.04+:

sudo nano /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
allow-guest = false