Umberto:
Thanks for your guidance. This is what I did:
- Removed bglmanx.dll from the main P3D folder and the simulator started normally
- Made several changes of airports (up to six different scenarios), and everything is normal
- The AV was enabled all the time with the exclusions of the couatl.exe and bglmanx.dll as you originally suggested (I could leave them in that way forever, it doesn't hurt)
In addition to this, I don't know why, it came to my mind an application that I have installed that you probably know, the Estonian Migration Tool (EMT), used for addons whose installers are designed exclusively for FSX, into P3D. At the time of the trials, after the installation of GSX, the EMT was enabled. I tried to run P3D again with EMT disabled and the bglmanx.bgl back into the P3D main folder, and P3D started completely normal. Thus, it seems that it was some kind of interference or conflict with bglmanx.dll and the EMT application.
At this moment, the simulator is running normally, with GSX installed with bglmanx.bgl into the P3D main folder, so I could say that everything is fine now. For me, unless there is a technical reason behind the possible conflict with EMT, I have no problem in making sure I run P3D with EMT disabled (I just use EMT to install old FSX addons, so no big issue there!). Probably some modules got corrupted, I don't know, I'm in no way an expert and too old to become one!.
Thanks again for your support and I'm now anxious to get all my FSDT addons into my P3D setup.
Best regards,
Edward