Many thx, Tim. It is very reassuring to receive a response at this time. What you said seems to mean that the raw reponse data are still sitting somewhere and could be retrieved.(?) I will hang around the forum for a bit and see whether there are any other suggestions. If not I will have to tinker with a backup version of the database and question_states, and I will let everyone know how it went. Hope that not too many people need that information, though... Peter

P.S. This is my event table. Should I reset the value of event in row 490 to 3 or 6? Thx, Peter

SQL result

Host: localhost
Database: moodleexam
Generation Time: Jun 26, 2006 at 01:52 PM
SQL query: SELECT COUNT( * ) AS `Rows` , `event` FROM `mdl_question_states` GROUP BY `event` ORDER BY `Rows` ASC LIMIT 0, 30 ;
Rows: 5

Rows	event
2	3
99	2
133	6
490	9
3501	0

Hello Tim,
unfortunately this is not the only drawback of this bug because as the code was:
            if ($action->event = QUESTION_EVENTMANUALGRADE) {
                question_process_comment($question, $replaystate, $attempt, $states[$j]->comment, $states[$j]->grade);
            } else {
the question_process_comment function was executed IN ALL CASES and this resulted in a complete erasure of a lot of fields (seqnumber, answer, event, grade, rawgrade and penalty) in the question_states tables including all students responses stored in the answer field (I must admit that I don't still fully understand why this happend so maybe there is a chance they are still there in your case)
So I hope to be wrong but based on my tests I would say that all your students responses (including responses for essay questions) were erased in the database for all quizes were the Regrade function was used.
Sorry to report such bad news.
I was just fearing this on saturday when I discovered the problem and this is the reason why I posted in this forum with a capital warning.