Originally Posted by
June7
Are these checkboxes bound to Yes/No fields?
If user should select only one (A or B) then this should be a single field, not two. If you want two controls and need to limit entry to one, use an OptionGroup control with 2 radio buttons. The OptionGroup control would be bound to the field and save the value (0 or -1) of the selected radio button.
Alternative is a combobox with two options - A or B which would be aliases for the 0/-1 values.
Make the field a required field and user cannot leave record without entering value. Access will nag user to enter data.
No code needed.