wolfsite: That's actually against TOS and can get both accounts banned.
Not supporting breaking TOS, but what?!?
Many times here people on GD(and staff as well iirc) have said it's ok for family to share games in the same household.
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SirPrimalform: 1. That's not how gifting works. GOG has a gift system but if your brother had used it then the games would be on your account. What your brother has done is buy the games for himself and then given you access to his account.
2. You need to contact support with the account that owns the games. Your brother owns the games, not you. Log in to his account or get him to submit the support request.
Both good points.....I don't see why the user above didn't have his brother buy the codes and then use the codes to add the games to his own account...would work a lot better/be smarter than what he has been doing, at any rate.
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PaterAlf: is there any chance that you are playing multiplayer with your brother and you both try to use the same key at the same time? That won't work and you have to buy another copy of the game instead.
Also buying 2 copies would help support gog a bit more. :)