Dears,

I've got one problem with redeem code for blood and wine.
It was my first purchase on GOG and I want to activate witcher DLC but after I entered my code and click "continue" I received notification " Some of the selected products require you to own the base game. " - does it mean that I should buy now the Witcher 3 base game to download DLC?
What are the options if I already have Witcher 3 on different platform and now want to activate DLC only?

Ummm..., why would you buy a different platform DLC than the base game that you own?

Kinda like if I need a steering wheel for a '65 mustang, and I get one from a '79 chevette and then wonder why it doesn't work?!?

It's a same content but from different supplier, anyway your comment did not help at all :)

That's because you have unreasonable expectations. You have bought TW3 on one platform, and want to activate an expansion on a different, rival platform. Can you not see the problem here?

But gog will not deliver Steam files - that's what you've got the base game for, I assume. You will have to get a refund and buy it on the correct platform.

If there's no other way I will just buy base game from GOG.
I was just not sure why I can't redeem code for DLC only.

either that, or get a refund for either platform.

steam releases normally include DRM, GOG does not. it is the same game, but the game's files, mainly the executable, are put together differently. that's why they're not compatible.

Not necessarily. First of all, Witcher 3 is DRM-free on Steam - if you uninstall Steam or make it inoperable and still keep W3 in the same location, it'll work without Steam launched. As for differing GOG and Steam API for achievements and such, it would be kinda dumb to create two separate .exe files just for that, you'll achieve significantly better results by detecting which platform is the game launched trough and using appropriate code.

The reason why GOG and Steam versions have to differ is content delivery - while, theoretically, GOG installer could potentially function on Steam version, Steam would "fix" the DLC by removing it the moment it detected discrepancy between your purchased version and your "modded" version. I imagine Galaxy would work in a similar fashion and besides, you can't even get any kind of installer from Steam. In other words, formats are not compatible and while it would be technically possible to mix them, it's not really a particularly good idea.

witcher 3 drm-free on steam... i did not know that. well, the more you know.

Everygame on steam is like that.
Steam just wraps itselft around the game, but the game per se doesn't search or check if it's being launched on steam.
Just open windows explorer and launch the game from it's .exe file instead of the steam client and you'll see what i mean.

that is not entirely true. most common these days is third party drm like denuvo or securom. and then there is steamworks, which creates it's own executable for each game, bound to your account. some sort of semi-drm, so to speak. there is an exquisite list of games, that are fully or partially drm-free on steam. but this is far from the norm.

Why? You can simply get a present, as me, to discover its useles, bcs you have the base W3 on DVD or a different platform. I understand a competition, but in this case it just sucks! Not everyone can afford to buy a product multiple times. ;)