I have Quantal (upgraded recently), and can confirm the problem. In fact the problem are non-english characters. When you upgrade, upgrade tool would disable old sources and add commnet they are disabled. In slovenian language comment is like: "onemogočeno ob nadgradnji na quantal". It contains slovenian character "č".
When I changed it to "onemogoceno ob nadgradnji na quantal" ("c" instead of "č"), everything works fine. It is a nasty bug for all who don't know how to edit sources.list from commandline, because you can not enable, remove or edit disabled sources from GUI tool. I think solution should be quite trivial, so it would be great if developers could solve that with higher priority. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1069019 Title: [software-properties-gtk] can not delete, enable or modify any software source with non-ASCII characters in the comment To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/software-properties/+bug/1069019/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs