I see that in that last image, the error notification still says "Your Windows Defender and/or another AV just blocked the installer". I'm assuming you don't have another AV, so it appears that Windows Defender could still be blocking the installation (at least that's what the installer thinks).

I use Avast One Gold as my AV, and as I said above, all I do is close ALL the shields for downloading and installing Captain Sim products. Also. None of the flight sims are installed on the C: drive (mine are installed on my E: drive). I'm not getting an error 24 message when installing them, so the installers are working fine.

I just downloaded from Captain Sim (using the Extended Download Service) and installed the B717-200 v1.1 (csm717_1100.exe), and it installed without any errors (image attached).  :-/

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