Failed to start LSB: AppArmor initialization

Dalla prima accensione dopo l'aggiornamento alla versione 16.04 LTS, esce questo errore: Failed to start LSB: AppArmor initialization. Non è più possibile scaricare applicazioni o aggiornamenti, l'applicazione "aggiornamenti e software" non si apre, appaiono continuamente messaggi di errore. In alto a destra è presente il simbolo di errore, il messaggio è: "errore nell'aprire la cache (E:no priority (or zero) specified for pin". ci sono dipendenze fra i pacchetti nuovi installati, come risolvo?

L'aggiornamento è partito dall'applicazione "aggiornamenti e software", non dal terminale, e si è concluso correttamente. Dal primo riavvio però si è presentato questo errore.

cat /etc/apt/sources.list# deb cdrom:[Ubuntu 14.04.1 LTS _Trusty Tahr_ - Release i386 (20140722.2)]/ trusty main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.

## Major bug fix updates produced after the final release of the
## distribution.

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu trusty partner
# deb-src http://archive.canonical.com/ubuntu trusty partner

deb http://it.archive.ubuntu.com/ubuntu/ xenial main universe restricted multiverse
deb-src http://it.archive.ubuntu.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties