I can definitly say that the Antivirus starts scanning only if coutl64_p3d.exe is starting recreating the cache but I already excluded C:\ProgramData\Virtuali.
Excluding %PROGRAMDATA%\Virtuali folder should be useful to prevent the antivirus mistakenly blocking Couatl exe to write ITS OWN private data there, but it shouldn't speed up the process because what is being written in %PROGRAMDATA% is fairly small and, more importantly, files are being created during the process so, it wouldn't be possible for the antivirus to scan *while* they are created. At best, it would have to wait until they are closed.
Of course, you would have realized that checking with the performance monitor: the files being scanned are the ones in your scenery folders so, these are the ones that need to be excluded. Lots of them are in the simulator own folder, but many might be elsewhere, in folders pointed by the various add-on.xml files but, in some cases, you might have sceneries that are not in the sim own folder and don't use an add-on.xml so, you can find them in external folders in the scenery.cfg.
So, basically, each and every folder that contains sceneries must be excluded and this (TOGETHER with having excluded the WHOLE Addon Manager folder) will surely prevent the antivirus from needlessly scanning .BGL files at each start.
I checked it right now and, I think it MIGHT be related to FsLabs warnings about the sim not being started with admin permission so, it will restart it automatically with changed permissions. It's possible this might trigger an antivirus response because, the automatic restart is run with different credentials than the ones you start the program with, so the antivirus is freaking out, because it assumed somebody (possibly a virus) started the program instead of you.
I changed the Compatibility options for Prepar3d.exe to always run with Admin settings, so FsLabs won't issue its warning anymore, and now I can confirm Windows Defender is NOT scanning scenery files anymore. The cache regeneration takes exactly 1 second on my system, most of the time is completed before I can even read the message.
While doing this test, I found MsMpEng.EXE was even scanning the P3D Shaders folder!! So, a new suggestion to speed it up and make it even more reliable is to add this folder to the exclusions too:
%LOCALAPPDA%\Lockheed Martin
This doesn't obviously have anything to do with GSX, it's just further evidence the antivirus doesn't really know what it's doing, other than doing its best to cause issues and slow your system down, and I wonder what will happen if the antivirus decided to *block* a shader...
