Private Sub Worksheet_Change(ByVal Target As Range)
On Error Resume Next
Range("B3:B" & Range("B" & Rows.Count).End(xlUp).Row).AdvancedFilter Action:=xlFilterInPlace, Unique:=True
If Application.Subtotal(103, Columns(2)) <> Application.CountA(Columns(2)) Then
MsgBox "bla bla bla"
End If
End Sub