[Bug 1790250] [NEW] Cannot calculate upgrade when trying to upgrade from 16.04 to 18.04

[Zonghao]

Public bug reported:

I can't seem to have my ubuntu 16.04 upgrade to 18.04.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.25
ProcVersionSignature: Ubuntu 4.4.0-134.160-generic 4.4.140
Uname: Linux 4.4.0-134-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Fri Aug 31 21:23:17 2018
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to xenial on 2018-09-01 (0 days ago)
mtime.conffile..etc.update-manager.release-upgrades: 2016-12-03T12:36:03.823555

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug dist-upgrade third-party-packages xenial

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-release-upgrader in
Ubuntu.
https://bugs.launchpad.net/bugs/1790250

Title:
  Cannot calculate upgrade when trying to upgrade from 16.04 to 18.04

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  I can't seem to have my ubuntu 16.04 upgrade to 18.04.

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: ubuntu-release-upgrader-core 1:16.04.25
  ProcVersionSignature: Ubuntu 4.4.0-134.160-generic 4.4.140
  Uname: Linux 4.4.0-134-generic x86_64
  NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
  ApportVersion: 2.20.1-0ubuntu2.18
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: Unity
  Date: Fri Aug 31 21:23:17 2018
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to xenial on 2018-09-01 (0 days ago)
  mtime.conffile..etc.update-manager.release-upgrades: 2016-12-03T12:36:03.823555

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1790250/+subscriptions