This notice pops up, and continues to pop up (creating dozens of these dialogs) when I select the approach tab. Flying KORD - CYYZ, running P3D 3.4, PMDG NGX, approach was ILS 24L, using Navigraph up to data navadata. Also happened a flight or two ago, flying in KSFO, ILS 28L. I finally have to force close the EFB DisplayUnit.   Two computer setup, that has been solid for years.   What next?   * Orest