You don't actually need a checkbox to select a record. Simply clicking in a control for ANY record selects it. Are you sure you can update the query that the form is bound to if you just open the query? If the form is bound to a table, can you update the table by opening it in DS view. If you can update the record outside of the form, then there is something in the form that is locking the record. If you can post the database with a little test data, we can take a look. There are many things that could be causing the locking.