Comment 3 for bug 803709

It may be that the reason your shutdown stops there is because there are unattended upgrades in progress at the time, and so it waits for them to finish.

Your screenshot definitely shows two related bugs:

 - plymouth is failing to launch the splash screen for you. This is a bug in plymouth (though I don't know what might be causing it).
 - unattended-upgrades is configured to report the status of any running upgrades via plymouth, but this *isn't* where the "checking" message is sent, that message is sent to the console. Even though we want proper plymouth integration and we want the message to show on the splash at shutdown, unattended-upgrades should *also* send status to the console, for consistency there.