Driver: San Francisco for PC was rendered unplayable despite being 'fine' during the transition. Anno 2070 was also suffering. Most titles were to be "impacted" by the move.
"We apologise for the inconvenience, it seems some of you can't connect to games announced as playable during migration," twittered Ubisoft. DRM is the cause.
Those definitely ruled out for play during the server switch were Tom Clancy's HAWX 2, Might & Magic: Heroes 6 and The Settlers 7, while Mac gamers lost Assassin's Creed, Splinter Cell Conviction and The Settlers.