So I just re-installed my Antivirus which includes a "desktop-firewall" I put it into interactive mode so I could create my own rules.

I was about to run TW3 when a popup opened asking if I want allow witcher3.exe to communicate with a remote host which I denied and created a rule for that.

Then another popup opened asking if I want to allow witcher3.exe to allow a UDP connection to the same remotehost which I denied and created a rule for.

Fact is: Since then I cannot start witcher3.exe anymore as it will crash!

This feels like DRM to me and I feel deeply betrayed!!!

I didn't use galaxy - It is the exe in ..\The Witcher 3 Wild Hunt\bin\x64 which shows this behaviour. Howver the Service of Galaxy might still be running in background (gonna check now).

Edit:
Service is not running and set to manually....

Edit2:
Yes you are right the Galaxy Client will be run by witcher3.exe and when it runs it will enable the Galaxy service....
(Going to remove Galaxy and its services now)

Edit3:
Delete Firewall rules
Uninstalled Galaxy using Windows
Ran cmd.exe (adminmode)
sc delete "GalaxyClientService"
sc delete "GalaxyCommunication"
Re-created Firewall rule
Game started like I hoped

Conclusion:
GoG Galaxy IS DRM!

Some people may miss the sarcasm here.

GoG should tell people upfront that an active internet connection is required to play (at least witcher3) via their Galaxy client. Might save them from posts like mine ;)

Um, I always play offline, and also stopped using Galaxy since I didn't care much for it. Game still works like a charm. If they use any "DRM", it's not particularly effective...

Do you happen to know what "remote host" it was connecting to, either by name or IP?

Some games request network access due to the underlying architecture and components but don't actually send anything beyond the system itself; the components may be communicating with one another via loopback, which requires network access, though not an active internet connection.

Then just don't use the Galaxy Client.

You have absolutely no idea what DRM actually means.

ks384123.kimsufi.com on UDP 514 (46.105.121.139) (you can see it on the picture in post #1) Oh then please enligthen us with your knowledge.

Its defo not drm, as my bro as given me a copy of his game, runs fine under my own account and never asked for activiation once, not even for firewall rules, but those popups you mention allow gog to keep the game updated.
An internet connection isn't needed to play at all, its just needed to keep the game up to date, maybe some downloaded games need that first connection on set release date and that's it.

Fairly sure it's stated somewhere, you might have missed it

Well - an simple way to test it, is to pull out your network cable and then start the game...

Oh - and that Ip adress is located in France. Seems to me it has nothing to do with G.O.G., but I can be mistaken..

When using galaxy, the witcher tries to use it because it assumes if you have galaxy installed... you want to use it.

It's not drm, it's communicating with the server to record play time, tell your friends, what you are playing, and record achievements.

It IS on the other hand a bit wonky in that if you block the connections, it should proceed to try to launch without galaxy. But this is called bugs not drm...

It's also without Galaxy. W3 wants to call home. Didn't allow that in my personal firewall, but game works anyways.