You do have several packages installed that aren't from the official Ubuntu repositories
Obsolete: boot-repair boot-sav cordova-cli curlew dus freshplayerplugin gloobus-preview google-chrome-stable google-earth-stable guidus intel- linux-graphics-installer mkusb oracle-java8-installer sublime-text viber woeusb -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1722643 Title: Upgrade from ubuntu-gnome 16.10 to 17.04 fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1722643/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
