For the first issue, consider posting the sql statement(s) that populate the table & fields where the values are missing, or if the append/updates are done via code, it would be better to see a copy of the db. There may be a failure in a query WHERE clause, or a coded variable that isn't always assigned a value. Either would probably be too hard to spot just by reading your sql or code, so looking at the db itself might be the only way. Or you can try to modify one of the existing problem records first and see if it will update through your form. You are using forms and not editing directly in tables, I hope.
EDIT: as an afterthought, by any chance have you deleted records from a table and what you have going on there is a Cascade Delete because of relationships you've created?
Last edited by Micron; 04-24-2018 at 07:33 PM.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.