I have a simple Update Query in a database which updates the "Status" field of a linked SharePoint List, for a specified record, according to another internal table.

When I run this query I get a Run-time error '3812': which states I the value I am trying to update is not valid or would break a data integrity rule.

This I very inconsistent, as it will update some records but then stop on others. I can then manually update most records in the database, but the others which are causing the Run-time error, I can go to the SharePoint list and update the status directly.

If it was a true data integrity issue, I wouldn't be able to update the field on the SharePoint list at all!