Thanks for the reply Umberto.
The whole story...I had a P3Dv4.2 system on a Win10 machine. Had GSXv1 and most FSDT/FlightBeam airports installed and active. A few weeks ago, I updated to P3Dv4.3. I did not check for FSDT/GSX operations, because I did not "go anywhere". Last week, I installed QW 787, and decided to use GSX and a FSDT scenery(KDFW) I noticed that GSX was unavailable in the Add-ons tab, as well as the scenery was the stock airport. Ummm, why?
I used the Live updater, and it tried to update, but came back with an error and it said I needed to update using the complete GSX 2.5 installer. I went to the FSDT site, found the new v2.5 installer, and downloaded the package(1GB+) installed it. I did not remove the earlier version of GSX, prior to install. Then when booting up P3Dv4.3, I noted that again, there was no GSX, Addon Manager, Couatl settings or Live update in the Add-ons Tab. So, I downloaded from the FSDT site, the Addon Manager, actioned it, and its actions took much longer than the previous install package. I noticed that it installed the C++ packages.
When I re-booted machine and opened P3Dv4.3, GSX, Addon Manager, Couatl settings and Live update were now in the Add-ons Tab. So, some how, on my machine, the later use of the Addon Manager.exe after full install had managed to get GSX etc in the Add-ons tab.But, as reported above, all sceneries were noted as in trial mode...I used the Reinstall button, and it asked me to input the Ser No. I did this for KDFW. I then noticed that all FSDT sceneries were noted as installed and active...sort of like when I did one, FSDT found my other serial numbers....
Now, you might say, this is all Impossible...On my machine, this is what happened. Usually when I update P3D, I have to always reinstall the ser No for one FSDT scenery. No big deal, I just need to realise what needs doing. Umberto, I need to get better control of my Avira virus manager, as while I disable it for initial download/install etc, I have no idea how to quarantine FSDT, so, this could be my issue?