Ubuntu 16.04 установить проблему с оснасткой

Возникли проблемы с установкой / удалением snapd.

Моя версия оснастки на моем Ubuntu 16.04 по какой-то причине неверна:

snap --version
 snap    2.31.1~14.04
 snapd   unavailable
 series  -

Поэтому я хочу переустановить snad вручную, используя:

sudo apt-get install snapd

и получить ошибку :

Errors were encountered while processing:
 /var/cache/apt/archives/snapd_2.33.1~14.04_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Я решил удалить эту версию, пытаясь использовать эту команду:

sudo apt purge snapd ubuntu-core-launcher squashfs-tools

, давая мне такой результат:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package 'ubuntu-core-launcher' is not installed, so not removed
The following packages will be REMOVED:
  snapd* squashfs-tools*
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
After this operation, 79,3 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 312065 files and directories currently installed.)
Removing snapd (2.31.1~14.04) ...
Failed to stop snapd.autoimport.service: Unit snapd.autoimport.service not loaded.
Failed to stop snapd.socket: Unit snapd.socket not loaded.
Failed to stop snapd.service: Unit snapd.service not loaded.
dpkg: error processing package snapd (--purge):
 subprocess installed pre-removal script returned error exit status 5
dpkg: squashfs-tools: dependency problems, but removing anyway as you requested:
 snapd depends on squashfs-tools; however:
  Package squashfs-tools is to be removed.

Removing squashfs-tools (1:4.3-3ubuntu2.16.04.1) ...
Processing triggers for man-db (2.7.5-1) ...
Errors were encountered while processing:
 snapd
E: Sub-process /usr/bin/dpkg returned an error code (1)

Команда :

apt-get -f install

тоже не помогут.

~$ apt-cache policy snapd

snapd:
  Installed: 2.31.1~14.04
  Candidate: 2.33.1~14.04
  Version table:
     2.33.1~14.04 500
        500 http://archive.ubuntu.com/ubuntu trusty-proposed/universe amd64 Packages
     2.32.9 500
        500 http://ru.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
     2.32.9~14.04 500
        500 http://archive.ubuntu.com/ubuntu trusty-updates/universe amd64 Packages
 *** 2.31.1~14.04 100
        100 /var/lib/dpkg/status
     2.0.2 500
        500 http://ru.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

Пожалуйста, если вы знаете, что происходит и как это исправить, помогите мне:)

Редактировать:

Надежные пакеты, которые у меня есть в списке источников:

deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse