Hi. In src/sbcl.lisp, the (defgeneric schedule-object ...) doesnt seem to be updated to new argument-count And down in src/scheduler.scm, the last method-defintion puts 2 'start args in the lambda-list: (define-method* (schedule-object (obj <pair>) start start sched) ;; CHANGE: this now calls its self recursivly as it should (dolist (o obj) (schedule-object o start sched))) -anders