You will get that message the first time since logging in that Carbonite attempts to get data for an item and the item is not in your local cache files. Previously Carbonite always attempted to get the missing item data from the server, but that can cause a disconnect if the server has been recently reset, which is why it asks you now. Each time a new version of WoW is released, the game clears all your cache files. That means all the items in the Warehouse or Guide that are not actually in the inventory of the current character will have the be fetched from the server. That can take many minutes, so if you switch characters it may ask again until all the items it needs are on your computer in the cache files. If you select no, you will end up with many ? icons in the Warehouse or Guide and as you mouse over each icon you will see the tooltip say "getting data" until done and then the tooltip will switch to the correct text.