Can you try using the update-manager again and report back? It may have been a temporarily downed mirror server.
** Changed in: update-manager (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/773625 Title: unable to complete download of upgrade packages -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs