A bug was found in the latest commit of the hl-todo package, which has now been reverted in the last hour https://github.com/tarsius/hl-todo/issues/56 If you get the error user-error: Cannot enable hl-todo-mode without font-lock then either do a package rollback, try another package update, or delete the hl-todo package from your .emacs.d/epla directory to force a new download.