Many Ubuntu systems have a minor bug when shutting down. Instead of displaying a splash screen indicating the progress of the shutdown process, the user is dropped out to a console screen flooded with shutdown notices (mostly network error messages). These messages are normal and expected, there is nothing to be concerned about. But it can be a bit unsightly, and it would seem that the Ubuntu team intended to have those messages hidden by the splash screen. The splash screen can be restored without much effort:
* Go to System → Administration → Login Window, and select the Local tab
* Select a different theme, then re-select the default theme (“Human”). This just refreshes the setting
* Click Close, then go back to System → Administration → Login Window, and select the Local tab again
* You’ll notice that the settings are different to what you’ve just chosen. Restore the setting to their defaults — Choose Selected only from the Theme drop-down box (instead of “Random from selected”), and re-select the default Ubuntu theme (“Human”). When complete, click Close. The setting will have saved properly this time, and the shutdown splash screen should work as intended.