The configuration file is fine, it is the default value that's commented out.
Please check unattended-upgrades logs if it performed kernel removals: zgrep 'unused kernel' /var/log/unattended-upgrades/*.gz Also please check if it ran at all. ** Changed in: unattended-upgrades (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/1914278 Title: apt autoremove is not removing unused kernels To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1914278/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs