Preventing Guest Mode and User Login

It's important to set the Lost Devices OU to prevent users from logging in. Otherwise, they can tap CTRL+ALT+S to skip the loading of the kiosk app then login and use the Chromebook. By disabling login it won't allow them to log in if they try this.

In your Google Admin console, choose Devices from the left hand menu. Under that menu, select Chrome, Settings, then Device.

Select the Lost Devices OU, then select the Device Settings tab. Scroll down to the Sign-in settings section.

Set Guest Mode to Disable guest mode.
Set Sign-in restriction to Do no allow any user to sign in.

Now we can move to the final step, Setting the Lost Device OU.