Are you on a stable release? update-manager does not show all available updates by design, as they are rolled out in phases:
https://wiki.ubuntu.com/PhasedUpdates apt currently does not implement phased upgrades, so it shows more upgrades ** Changed in: update-manager (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1854162 Title: software updater will not launch following the latest update To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/1854162/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
