Jtdcftul

I tried to update from Xubuntu 14.04 to 16.04 using the sudo update-manager -d command, however, it stopped after the first step of the update due to poor internet connectivity and I closed it. When I re-attempted an upgrade with the same command, 16.04 was not being shown as an update possibility in the Software Updater. Instead when I used update-manager -d, I could only see that the update to 16.04 was available, but could not actually update because it needed root privileges. What might be going wrong?

Thanks in advance :)

Try this:

First: You need to update the system.

Open a terminal,

Press Ctrl+Alt+T

Run it:

exec sudo -i

apt-get update

apt-get dist-upgrade

apt-get autoremove

apt-get clean

Now edit the file /etc/update-manager/release-upgrades and change the value of Prompt from normal to lts, continue running:

nano /etc/update-manager/release-upgrades

Ctrl+O Save File

Ctrl+X Close nano

Reboot your system to finish installing updates, and to upgrade to new available version:

Open a terminal,

Press Ctrl+Alt+T

Run it:

exec sudo -i

do-release-upgrade -d

Software Updater will show up and search for the new LTS release

However, Ubuntu 16.04 is available now.

Press the button Upgrade to start upgrading to Ubuntu 16.04.

The Software Updater will ask you to confirm still you want to upgrade, press Start Upgrade to begin installing Ubuntu 16.04.

Now, the Software Updater will prepare to start setting up new software channels, and after a few minutes, the software updater will notify you the details the number of packages are going to be removed, and number of packages are going to be installed, press Start upgrade to continue.

Ended the dist-upgrade, reboot your system and:

Open a terminal,

Press Ctrl+Alt+T

Run it:

exec sudo -i

dpkg --configure -a

apt-get -f install

apt-get update

apt-get dist-upgrade

apt-get autoremove

apt-get clean

I had the same problem as you have. I did EXACTLY what you did and ended in same results: upgrade failed! When you change Ubuntu version you do an upgrade. A (ubuntu) distribution upgrade. When you change only any software version you do an update.

After three days of trying i gave up and downloaded an ISO image and installed it via liveUSB.

Anyways, you should be aware that an upgrade is possible via LiveUSB and it is faster than the Terminal command upgrade. USB file transfer is faster and much more reliable than an internet connection. I personally prefer do to a completely new install with each Ubuntu version because i don't inherit all the junk from previous one and i don't mess up the sources list with wrong ppas. It's actually very simple: boot up the LiveUSB, enter the desktop, click the Install Ubuntu icon and choose the "Replace Ubuntu 14 with Ubuntu 16" option.