Cannot upgrade from Ubuntu 14.04 to 16.04

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.

Hello. I just did an upgrade from 14.04 to 16.04.

My PC locked up during the process of dpkg setting up packages. I reset the machine and then ran this command:

sudo dpkg --configure -a

mySQL package failed to install and so I had to find that process and pkill the start process (from an alt terminal), then dpkg would continue.

I was left with an unstable system and could not obtain any network connection, eth0 or wlan0

I then ran sudo dpkg -C
Output:
The following packages have been unpacked but not yet configured.
They must be configured using dpkg --configure or the configure
menu option in dselect for them to work:
 apparmor User-space parser utility for AppArmor
 console-setup console font and keymap setup program
 console-setup-linux Linux specific part of console-setup
 kbd Linux console font and keytable utilities
 mysql-server MySQL database server (metapackage depending on the lates
 ubuntu-minimal Minimal core of Ubuntu

The following packages are only half configured, probably due to problems
configuring them the first time. The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 haproxy fast and reliable load balancing reverse proxy
 initramfs-tools generic modular initramfs generator
 mysql-server-5.6 MySQL database server binaries and system database setup

I then ran these commands in this order:

sudo dpkg --configure initramfs-tools
sudo dpkg --configure apparmor
sudo dpkg --configure mysql-server mysql-server-5.6
sudo dpkg --configure kbd console-setup console-setup-linux
sudo dpkg --configure ubuntu-minimal

haproxy still not working but all of the rest are fine and the network subsequently regained a connection. Seems now to be a successful upgrade. I suggest you check your dpkg config with this command:

sudo dpkg -C

Status changed to 'Confirmed' because the bug affects multiple users.

This is a known issue, mentioned in the Xenial release notes: "14.04 LTS to LTS upgrades will be enabled with the 16.04.1 LTS point release, in approximately 3 months time." I imagine there is a main bug somewhere but I can't find it.

I'm going to assume the Russian text is the usual upgrade-failed report, which is:

"An unresolvable problem occurred while calculating the upgrade.

This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal."

thanks.
i did
"* Unofficial software packages not provided by Ubuntu"
and everifing worked out.

Hello, French version :
"Impossible d'évaluer la mise à niveau

Un problème insoluble est survenu lors de la préparation de la mise à niveau.

 Ceci peut-être dû à :
 * la mise à niveau vers une version de développement d'Ubuntu ;
 * la version de développement d'Ubuntu est actuellement utilisée ;
 * des paquets logiciels non officiels, non fournis par Ubuntu.

Si rien de tout cela ne s'applique, veuillez signaler ce bogue en utilisant la commande « ubuntu-bug ubuntu-release-upgrader-core » dans un terminal."

I am on a Dell XPS 13 (2015) 9343 with Dell installed version of Ubuntu 14.04 (upgraded to 14.04.5) is that can be a source of the bug?
I don't not what to do to fix and upgrade to 16.04