Even though you have all the 3rd party options unticked you still have xorg packages from a PPA and the versions of those packages are greater than the release to which you are trying to upgrade so the upgrade calculation fails. You'll need to use ppa-purge to remove that PPA.
** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1681197 Title: 16.04 - 16.10 to 17.04 upgrade fail To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1681197/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs