pcsteamtechnical-issuesubisoft-connect
I have bought a Ubisoft game on Steam, and bought its season pass product key on a retail website, which happens to be for UPlay.
It seems that I have wasted my money. That, I accept. Now, I want to buy the base game for UPlay as well because it is cheaper to buy DLC on Steam.
My question is, if I try to activate a product on UPlay, which I already own in Steam, will it say you already own the product or will it allow me to activate the base game and play the bought DLCs?
As of the Steam Discovery Update on Sept. 23rd, 2014, Steam itself now shows you the DLC you own in the Store page without having to use browser extensions or look at the game properties in your library.
The blue markings on the left side of each DLC entry indicate that I own it already and if I hover over it, there will be a popout that shows that it's in my library.
Note that isn't perfect. In this particular example, Steam shows that I don't own Wonders of the Ancient World, even though I do, but I'm guessing that's a problem with that particular piece of DLC, as it's done that since release. However, Steam still won't let you buy anything you already own, so you're safe from double purchases.
You are indeed boned, good sir.
The UPlay system has been designed in part to discourage used game sales. In order to gain access to this game on UPlay would require you to also gain access to the account it has been registered on, and in the process gain hold of the email registered to that account, etc. This would of course require you to track down the person which traded in the used copy and convince him to part with his account in which he may have registered other games that he may wish to keep.
Contacting Ubisoft will probably not help much. Their representatives are not obliged to help you in this matter. If they choose to help you, you are in luck. I would not count on it however. I think the greatest chance for a refund is for you to take the used game back to the reseller and explain the situation and hopefully get some form of refund.
Best Answer
As Steam and UPlay are totally different platforms and do't share the same account, there is no way, that each platform could know about the games on the other one. Therefore my answer is, that you can activate the base game on both platforms.
Also if that wouldn't be possible, then the game should automatically be in your UPlay library if you activate it on Steam.