winner already has game in the inventory

Ask for a reroll.

There is a "request new winner" button. I think that's when you use it.

AFAIK, it's not against the rules to own the game, though it might be "ethically questionable".

If you put a rule in your giveaway you need mod approval. Public giveaways can't have special rules, only private giveaways or giveaways for private/very small groups.

Edit: I took the extra mile and crawled the forum, here's a mod's comment on the issue

Are there rules against having a copy of the game in your inventory?

Pretty sure there's a rule (or guideline maybe) that says 'do not enter giveaways for games you already own'.

ask for reroll, with screenshot from his inventory

AFAIK, there isn't a rule against having the game in their inventory - after all, that copy might be for a friend or for one of their gifts?

You could ask for a re-roll, but I'm not sure which way the staff will favour.

And for special rules (i.e. your describe it so only a person without the game will win), you need permission from support and rules can only be applied to private giveaways or (maybe) giveaways for small groups?

It is allowed for them to enter and win. I've entered for games in my inventory in the past as I've bought copies for giveaways or just gifts, even wishlisted items.

People recommending you reroll need to look at the rules again. The rule about not owning a game refers to their library, not the inventory.

You must give the game to the winner, there's nothing wrong to have the game in inventory. I enter for the games i have in my inventory or have the keys. It's only not allowed to have the game in library.

It would probably help if the rule was specific about games only in your library.

I would cancel the giveaway and make another one.

Game activated/added to the library = already owned, cannot enter giveaways for the same game.
Game in the inventory, but not present in the library = allowed to enter giveaways, no problem whatsoever.

Your winner is eligible for your giveaway, unless you created a group/private giveaway and had a special rule approved.

Give him the game, many times i bought games who i dont have and let in my inv to make ga´s, and, entered in ga´s of the same game
i dont see a problem in this

To me, whether it is "allowed" or not is irrelevant. Your giveaway, your rules, whatever the site might say.

If you don't want to give the game to someone who already owns it in whatever form(yes, having it in your inventory is owning it), then don't.

Request a reroll first. If the mod isn't a jerk, he'll understand and approve, with less hassles for everyone.
If not, well...don't give in anyway. Pick someone else who entered, by yourself, and give it to them even if they didn't "officially" win. You'll have a red mark on your record, but it's better than giving away against your will, and you've still made someone happy which is the whole point of this thing.

Would be good form to let it be known beforehand in your GA description though, so people are warned.

Peronally speaking;

For example I have E.Y.E: Divine Cybermancy in my inventory.However I bought it in order to gift in in this site.So I am entering E.Y.E giveaways.However it is impossible for you to know my intention in the first place,so I don't blame the maker if he/she wants the reroll.Listen your guts and decide.

thats why my inventory is private, so no crying from giveaway creator

Unless it is not in his library, it is not a valid request for a reroll

Whatever each individual may think about these cases, the site rules view 'game owned' as 'game in library.'

I've also entered giveaway of games I gifted personally to my friends but haven't purchased one for myself.
(Did avoid games in inventory to avoid this.)

YOU HAVE TO GIVE HIM the price, otherwise you will get banned on SG
if you dont like to give games out to people who already owns it then make this clear in the description within the giveaway.

its your fault and he has the right to get the price cause he WON

I, as many other contributors, often buy multiple copies of many games that are on sale for sake of GAs and puzzles. Even the ones we have wishlisted. It doesn't mean I wouldn't like to own a copy for myself.

And what about traders - the game mey be "saved" for upcoming trade.

Also you don't even take into considerations thing others than SG/trading. A lot of ppl who are gamers have gamer friends. I may buy a gift copy of a game for friend's birthday and keep it in my inv until it's his BD.

You have no clue what the winner intended to do with his giftable copy - yet you simply jump to conclusion that he want's to "steal" the game from you.

thx for all the answers, most where usefull
user "dohlicious" added me on steam and called me names though this question was not because it happend, it was just in case
before i could wrote him back he deleted me