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I agree that a complete re-install is probably the only solution. However, I think you should install the expansions in the order in which they were released. It's ok to add expansions out of order when you first buy them, but for a major event like this, I'd go with the release date order. Also, as painful as it is, it's a good idea to re-install your game periodically. We would typically recommend doing it with every new release, but now that there are no new releases coming, I recommend doing it every few months.