Hello! I have had this issue on my previous flightsimming desktop and am still experiencing it after upgrading to a newer one recently. And that is that, after a period of time, Navigraph Charts loses its connection and nothing short of restarting the machine has any effect. I’m running Prepar3D v. 5.3 with a PMDG 747-400 QOTSII on a long flight, TPA to HHN in this case. Navigraph is running in a window on the same machine. After about 3 hours of flight time the aircraft symbol disappears and any attempt to bring it back generates an error indicating that the connection cannot be reestablished.
If there’s any amplifying info I can provide please do not hesitate to ask. Thanks!