Can't upgrade from Trusty To Xenial with "Can't calculate the upgrade" error

[Ahmed Faisal]

when I tried to initiate the do-release-upgrade -d command, after calculating the upgrade -2.2 gb of downloads- It begin to download the packages. I had to leave the office so I disconnected the network first. it start to loop through the repositories and then reset the upgrade process and left safely so I turned off the laptop.
then I tried to do that again in my house to be faced with "cannot calculate the upgrade" error. no matter what I do it just pops up over and over again.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.19.0-49.55~14.04.1-generic 3.19.8-ckt12
Uname: Linux 3.19.0-49-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
Date: Sun Feb 21 13:54:24 2016
InstallationDate: Installed on 2015-10-01 (143 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-02-21 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2016-02-21 13:50:37.188988
 Log time: 2016-02-21 13:53:18.868511
 Log time: 2016-02-21 13:54:23.467569
 Log time: 2016-02-21 13:54:43.313736

[Ubuntu Foundations Team Bug Bot (crichton)]

You seem to have installed the cinnamon package on Ubuntu 13.10. Unfortunately, that package is not available yet for 14.04. To upgrade to Ubuntu 14.04 LTS you'll need to either wait for a fix for cinnamon to be available or uninstall the package and then upgrade.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]