Here you can see the official reply from GOG as well as a workaround regarding the issue.

did antivirus software ever actually helped someone against something ? I always only see complaints about false positives.
It is rather funny that people still have faith in the promise from AV sellers that "we can even detect unknown viruses by some clever heuristic analysis". Despite plenty of evidence that this simply doesn't work.

You have the option to turn that off (although most people don't do that). But don't forget the real threats that will be blocked as well. Here AV software is immensely useful and prevents harm and hijacking in most cases.

at least that's what you hope ;)

is that something that you believe ? or actually have seen happening ?
that's what my question was all about.

Yes, I have experienced that myself. Otherwise I would not have written it. I once was blocked from opening a specific file and since it should be an unofficial patch I thought that it probably would be a false positive. So I turned AV off and opened it. In mere seconds I had hundreds of icons, and hijacked adresses and the only way I was able to revert this was to rstore a recovery point. I tried for hours to get it back manually before I had to use it. Be aware that I know my way around my OS pretty well so I know were to look and how to fix most of the things. This was just too much. I should have "listen" to my AV in this case.

You're positive? On which virus?

I have a severe case of FullaShitness.

That sounds so negative! ;-)

ok, there is certainly a point for checking downloads from unknown/doubtful origin prior to opening them.
But you can do that manually, you don't need to have to your AV app always running and automatically scan each and every file in your system.

Especially in this case: AV throws a warning about Galaxy, the forum/GOG tells you it is a false positive and you ignore it. If you trust the source/origin of the application/file more than your AV scanner, what is the point of scanning it?

same thing when you get a warning about one of the offline installers

PS.: what's ratio between actually valid warnings from your AV and (annoying) false positives ?

That's the reason you have exception lists and options. I've set my AVG to just scan what I think myself could harm me. I nearly have zero false positives so I would not consider it annoying at all. I also don't get that many warnings - mostly in browsing some hijacking(or additional page loading is prevented so this helps me a lot.