You seem to have some python3 packages installed from a PPA which are causing the upgrade to fail to calculate. Here are some of them:
libpython3.6 3.6.3-1+xenial2 1 libpython3.6-minimal 3.6.3-1+xenial2 1 libpython3.6-stdlib 3.6.3-1+xenial2 1 Please install the package ppa-purge and use the tool ppa-purge to remove the PPA and the packages which it provides. ** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1780567 Title: Impossible to upgrade to 17 from 16.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1780567/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs