Then the loading order is visible by indices next to activated mods 3. To change the loading order, activate the Show loading order checkbox below the table 2. Click the icon to go to the Workshop page, where you can subscribe to the missing mod or see the mod troubleshooting section for further information. 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. To enable a mod, click on a gray toggle in this column, to disable it, click on a green toggle. Enabled displays if the mod is enabled (green) or not (gray).
