I think that the problem comes from sunbird. You have a version karmic and there is a rule "Replaces: libnss3" which holds back libnss3. Because libnss3-1d is renamed to libnss3 during the upgrade to Natty the upgrade fails. If you remove sunbird and its dependencies you should be able to upgrade.
Note that sunbird has been removed from the archive since Lucid and is available as Thunderbird Lightning extension. ** Changed in: update-manager (Ubuntu) Importance: Undecided => Low ** Summary changed: - Upgrade from 10.10 to 11.04 fails + Upgrade from 10.10 to 11.04 fails: sunbird/karmic holds back libnss3 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/760713 Title: Upgrade from 10.10 to 11.04 fails: sunbird/karmic holds back libnss3 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
