you need to edit your /etc/apt/sources.list file and remove duplicate entries (lines that are the same)
-- problème "update-manager" https://bugs.launchpad.net/bugs/310688 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs