I am receiveing the following message when I add data to a sub form: You can't assign a value to this object. *The object may be a control on a read-only form. *The object may be on aform that is open in Design view. *The value may be too large for this field. I don't know why the form would be a read only form or how to check for it? The form is not in design view It is not too large. The control is a combo box that is a lookup value in the underlying table. This combo box assigns values to several other text fields on the same form? Any ideas?