No, there are no processes related to the anti-virus running at all - it's completely blocked at the group policy level, and it's absence has been verified through both task manager, and command line process lists - you're welcome to inspect my process and service lists if you doubt my abilities there.
The antivirus low-level service won't be listed in the processes, because it's not a process, it's a service.
Please don't try to tell me otherwise, I personally witnessed by doing remote assistance on an user's system some antivirus can do that, the only way I could *know* it was blocking files, was to check the antivirus log because, even if it "looked disabled", with zero processes that could be found, it was still running, I guess some antivirus are able to run stealthy so they won't be seen by virus that try to intercept them.
Regardless of that, all relevant folders are (and have been since Windows was installed) completely excluded from it as well (in fact, the entire drive containing Prepar3d is completely excluded) so can we please move on from anti-virus now?
That's the first time you ever said you have Excluded the folders, so NOW we can "move on" from the antivirus.
more detailed logging is clearly needed to have any hope of diagnosing this issue. As a developer myself, at this point I would want to be logging (at minimum) specifics of which BGL files were being seen, their apparent size and if they could be opened or not (along with any appropriate error codes from whatever I/O library you're using)
As I've said, since this is the first time ever somebody had this problem in the 9 years GSX has been out, we don't have any more detailed logging because, until today, if there was some kind of problem accessing files, we properly catch the error and properly log it. That's the first time ever that files are not found but there's NO error, not even a crash, which is what would have happened if the program didn't properly handle an error condition.
Adding extra log information is surely possible, but it can't be done immediately, and would at least like to have *another* report.
Do you have another PC you can try GSX on ?