UPDATE : contacted Ubisoft Support via twitter : I had to uninstall Ulauncher from control panel and then download it again from here : http://t.co/Y0ecmAoAOd

Hi

I have bought the game from GreenManGaming, US version I assume. Anyway, after the Installion I have got the message "Uplay is required to play" although I already had it installed for Driver : SF. However, I did manage to activate it using the serial key I have got from GMG, so I tried to uninstall and reinstall from within Uplay. Unfortunately, that didn't solve the problem.

Does it have anything to do with the DRM thing?