When I tried downloading the FSX version of FSUIPC I got a virus warning from NOD32 telling me likely heuretic virus and a very likely threat.

I would ignore the warning.

False positive. Install it. And then look for a proper AV, or updates for the one you have now.Allcott

NOD32 is widely regarding in PC tech circles as the best AV app Allcot... It's not actually detecting a virus, it's the Heuristics engine thinking that there's something in the FSUPIC code that looks virus-like. It's a false positive for sure, but NOD32 is a very good program, never had an issue with it.

Then it needs an update. Tail wagging dog. If the virus protection causes problems with legitimate programs, then it's the thing that needs fixing. No need to debeate the efficiency or otherwise. Allcott