The fact that no one else has reported this makes me think it's user error, but I can reproduce with emacs -Q, so here goes:
Scheduling or deadlining an item with no existing SCHEDULE/DEADLINE errors out, because both call code like this: (let* ((old-date (org-entry-get nil "SCHEDULED")) (old-date-time (org-time-string-to-time old-date)) If there's no old-date, then "nil" gets fed to `org-time-string-to-time', which doesn't accept "nil". I adventured into git looking to see if something had changed recently regarding org-time-string-to-time, and it doesn't seem to have, which makes me all the more suspicious that I'm doing something wrong. But it still won't work with emacs -Q, so... What am I doing wrong? Thanks, Eric