I had the same issue but after updating and upgrading apt it worked fine. run these commands
sudo apt update sudo apt upgrade Then run the software update and it will work fine -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1799009 Title: Failed upgrade from Ubuntu 18.04 to 18.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1799009/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
