Received the 500 series Z Wave dongle a while back and had time to install it yesterday. At first everything seemed fine. All wired devices showed up after query. Then later in the afternoon, started getting responses from Alexa that Z Wave devices were not responding though they actually did turn on or off. Insteon devices not affected. Bringing up the AC, I had quite a few devices that had no comms. Tried to heal network and AC froze up before completed. Tried again, completed successfully. Then started getting messages about Z Wave devices and no communication. Some devices actually unresponsive that were earlier. Today decided to reinstall old dongle. Looks like back to normal, though waiting to see if anything goes south with time. I did do full back up of Z Wave network, am running 5.0.13A (installed 3 weeks ago), did disable query at start. I plan on trying the new dongle again but wondered if anyone had similar issues. It seems like most installs from comments here have gone fairly smoothly.