This may happen if you want to play a foreign savegame using different mods or might be caused by some technical problems of the Steam Workshop update mechanics or a mod being removed from the Steam Workshop due to legal reasons. Mods that are marked with a red triangle can't be found by the game. Be aware that it's unlikely that a mod author can test all possible combinations of mods so these indicators are a good estimation but no definitive information. There are some indicators that might serve as an orientation to estimate the impact. While in most cases it is no problem to activate additional mods at a later point of the game, deactivating mods may have a serious impact in the integrity of the savegame. Usually the mod description or the description in the Steam Workshop or download location contain information regarding load order, dependencies and incompatibilities. Make sure that you activated all dependencies if a mod requires some, too.

Some other mods might depend on scripts of other mods which have to be loaded before.

If you use some mods that override files of others or manipulate them by script, they might be needed to be loaded last. In many cases it is not required to change the loading order.

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