The point at which upgrade stops is after hitting bionic-backports. Here are the logs from screen:
Some third party entries in your sources.list were disabled. You can re-enable them after the upgrade with the 'software-properties' tool or your package manager. To continue please press [ENTER] Hit http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu bionic InRelease Hit http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu bionic-security InRelease Hit http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu bionic-updates InRelease Hit http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu bionic-backports InRelease Fetched 0 B in 0s (0 B/s) Checking package manager Reading package lists... Done Building dependency tree Reading state information... Done Calculating the changes Calculating the changes Could not calculate the upgrade 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. Restoring original system state Aborting Reading package lists... Done Building dependency tree Reading state information... Done === Command detached from window (Tue Nov 13 10:33:09 2018) === === Command terminated with exit status 1 (Tue Nov 13 10:33:19 2018) === -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1803036 Title: upgrade to 18.04 stops without errors To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1803036/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs