This is a sort of related problem (but if I ought to start another post, let me know), but we're using 1.6.3 and last month we had a LOT of trouble w/the built-in Reset button (in the Administration block) not entirely resetting quizzes. The fact that you could click the button, wipe out all the results, but still go into quiz results and be told "34 Students have made 34 attempts" drove our teachers crazy. I've read posts that mentioned that that's deliberate (in case someone needs to be re-enrolled without losing work). We worked around it by backing up and restoring courses without user data, deleting the originals, but that was a bit much for most teachers and we ended up doing most of it here at IT Training. Is there a better way to deal with this?
James