I have experienced this as well, but I'm not sure that it should be called a bug because the Update Manager detects the condition and handles it with a dialog.
Using "sudo apt-get dist-upgrade" does the trick - but only partially because then you get to a point where some of the packages cannot be found or downloaded. This seems to also prevent the Ubuntu Software Center from loading properly. (see https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/1003042) W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/main/source/Sources 404 Not Found , W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/main/binary-amd64/Packages 404 Not Found , W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found , E:Some index files failed to download. They have been ignored, or old ones used instead. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/999013 Title: Error: cannot upgrade to Quantal from Precise To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/999013/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
