[...] > It looks like a similar issue was discussed a few months ago, but I never saw > a final description of how to fix this problem. So, how do I clean up from > this? Hello. You are right, this is a rare periodic bug, in many regards authored by myself. It is typically hit by about 1 user in 1000 and it cannot be addressed by the upgrade script, because the solution depends on the data. I typically ask to send me a private email with the output of this query: SELECT AV.object_id, AV.attr_id, RO.objtype_id FROM AttributeValue AS AV INNER JOIN RackObject AS RO ON AV.object_id = RO.id LEFT JOIN AttributeMap AS AM ON AV.attr_id = AM.attr_id AND RO.objtype_id = AM.objtype_id WHERE AM.attr_id IS NULL; -- Denis Ovsienko