How to Disable a checkbox in another form while one is selected in another form

[msingh24]

I have 2 forms and I want to grey out a checkbox or option button in the 2nd form when one checkbox/optionbutton is selected in this 1st form
Please HELP!!

Thanks

[msingh24]

Private Sub opt5_AfterUpdate()
    opt5.Enabled = True
        If opt5 = True Then
            opt13.Enabled = False
                MsgBox "Due to similar course material, you will not be able to select A alongside B"
        If opt5 = False Then
            opt13.Enabled = True
    End If
    End If
End Sub

[twinnyfo]

You must refer to the Form:

Forms![FormName].Form.opt13.Enabled = False

[msingh24]

Thanks for the reply but having tried it,
it now gives me and error saying Microsoft Access can't find referenced form 'frmModSelect2' - - - Run time error - 2450

Also that is the name of my form

[twinnyfo]

Are you sure the form is open? Named properly? I know, stupid questions, but we have to ask....

[Rabbit]

Is it a subform? If it is, you need to reference it through the parent form.

[msingh24]

Thanks guys!! I have got it now