I'm fairly certain they did.

You should never use more than one security program of the same type. If you use the Sphinx firewall make sure to switch off the Windows firewall or you are asking for trouble with your system.

Yes. All games that were shipped with the alpha Galaxy libraries for multiplayer had them removed when the Galaxy beta was released. They were only a hand full of games anyway as far as I remember.

OK thanks. I've used 'Sphinx Software Windows Firewall Control' for years with no problems as it is designed to be a 'front end' for the built in Windows Firewall helping to easily create rules, etc. by showing a pop up when anything wants to connect somewhere. Everything has always worked perfectly until this Galaxy thing. If I allow a connection the game(s) will run, if I don't the game(s) crash :( As I don't know for sure where these games are trying to connect to I'd hoped to be able to set up a firewall rule in Windows Firewall itself allowing access to localhost for each of the problem games to bypass this issue.

I didn't know that Sphinx was just a front end for the Windows firewall. In this case you aren't actually running two firewalls at the same time.

Galaxy games should only connect to localhost. To be more precise they connect to the Galaxy service running on your computer. But the Galaxy service then connects to GOG's servers to relay all sorts of information. If you don't have Galaxy installed you do not need to worry about that. But you still need to allow the games to connect to localhost to check whether Galaxy is there or not.

I have never used the Windows firewall because it was way inferior to any other product out there when it came out. Even though it was improved over time I have always used better firewalls. So I do not really know how to configure it. I also can't really have a look at it because turning the Windows firewall on would interfere with the firewall I have installed. Try googling how to set up a rule for localhost in Windows firewall.

Ah great, another poorly programmed feature nobody asked for is now giving people trouble.

Thanks for your help. Further to all of this I've discovered that at least two Galaxy games actually connect to other IPs as well as the localhost. One also connects to 52.10.22.114 which is ec2-52-10-22-114.us-west-2.compute.amazonaws.com and the other also connects to 46.105.121.139 which is galaxy-log.gog.com. Not happy with this state of affairs at all and all because of an 'optional' feature that I actually do not want :(

One eternity later...
Patch v1.77_GOG_MP for "No Man's Sky NEXT" came with new Galaxy64.dll v1.132.1.0 (instead of old v1.96.0.0).
This version not crash with loopback connections blocked by firewall.
But "backporting" this dll to older game version is not possible due to major difference in list of exported functions (confirmed with use of dependency walker tool), I've received error message like "entry point for function CreateInstance not found".
It took more than 3 years to add exception handling...
Edit:
Or maybe developers of the game added exception handling by himself?

So... I cannot play a game that relies on that galaxy.dll even if I don't use Galaxy, unless I study OC programming thoroughly and tune some inner firewalls to imitate a response from connection? And it's not considered my money is stolen again, right? Is that our conclusion on that topic? Or is there a patch? I'm sure torrents have a working version. Which leads us again to the old question: why devs hate people who choose to support them so much? So much for no-DRMs...

I have this problem currently with Planet Nomads when blocking the game via a written rule in Comodo Firewall (5.12, because all later versions suck) even when allowing loop-back zone (127.0.0.1).
Interestingly, if I don't write the rule but just wait for the alert pop-up (it first tries to connect to an outbound IP, which I deny by hand, than it tries the loop-back, which I also deny by hand), and the game starts just fine, even though it never connected.
I think the reason is, while a written rule blocks the connection activity and directly, the error occurs while the other method provokes a timeout, which is silently disregarded by the galaxy.dll maybe interpreted as "no interface available". Maybe they just let it crash to push technical-unaffine users into giving up and just allow the connection and data siphoning.
As what I have seen so far in NMS, Dying Light and so on, I don't trust them anymore. And I don't buy here anymore.

The solution/hack described here may be worth looking at - although it addresses a different problem (running games using galaxy.dll on WinXP) it could be that "neutering" galaxy.dll would help here.

Hacked dlls, with injections should only be used from trusted sources. So, I would be cautious about them.
I just tested out of curiosity, what happens if the [PATH]/PlanetNomads\PlanetNomads_Data\Plugins/Galaxy64.dll is renamed to Galaxy64._dll, de-facto disabling it and even though PlanetNomads.exe still tries to connect to 52.241.52.229 and 172.217.168.14, it can be blocked by a firewall without any crashes.

So, unless you want to use Galaxy to get online with the game, just deleting this dll should solve the problem.

Good advice generally - but these have been online since Jan 2019, have source code and give a clean result on VirusTotal (results here).

Of course, if just renaming the .dll file works without causing the main .exe to crash, that would be a simpler option.

No, the reason is that they eventually got around to fixing the problem around 1-2 years ago. Newer versions of the galaxy.dll don't have the crash anymore.

Also let me remind you of Hanlon's razor: "Never attribute to malice that which is adequately explained by stupidity.". There isn't always a darker purpose behind every human error.

Joseph Heller (Catch-22) saw it the other way around: "Just because you're paranoid doesn't mean they aren't after you.”

We'll never know. So be vigilant and keep your guard up - they are after us.