I've finally found what was kicking this off, though I think it's more a symptom than a cause.
I had SMB shares auto-mounting. Removing them from fstab fixed the problem, lshal now gives output and update-notifier now works. >From the variety of fixes that have worked for people it looks to me like something in the start-scripts for hal is being brittle... -- hal-device-manager does not load https://launchpad.net/bugs/31517 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs