I experienced the same problem, I think it has been invoked by not first updating + upgrading + dist-upgrading to the latest version of 14.04 (.3 at the time of writing) before running do-release-upgrade
Besides resetting the /etc/apt/sources.list file to trusty, as suggested earlier, "pinning" to utopic sources as added by the failed do-release- upgrade has to be removed from the /etc/apt/preferences file. As also discussed in https://askubuntu.com/questions/615090/broken-upgrade- from-14-04-to-14-10/665663#665663 , I succeeded to fix it for 3 machines that all experienced this problem as follows: sudo -s cd /etc/apt #Remove potential pinning preferences mv preferences preferences_old #Restore sources mv sources.list sources.list.old cp sources.list.save sources.list #Clean apt cache apt-get clean #Possibly repeat this block until `lsb_release -a` shows 14.04.3 and no further update/dist-upgrades possible apt-get update apt-get upgrade apt-get dist-upgrade #Finally perform the release upgrade and reboot do-release-upgrade ** Changed in: ubuntu-release-upgrader (Ubuntu) Status: Expired => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1452968 Title: upgrade failed from 14.04.1 to 14.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1452968/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
