There are a small handful of mods that will not work with Cauldron or KCauldron and must be removed (In some cases on your launcher too) to be able to use plugins along with your mods/modpack.
The current known incompatibilites are:
- MobiusCore/Opis - Older versions do not work with any Cauldron versions, newer builds do work with Cauldron but not with KCauldron.
- FastCraft - This can still be installed clientside, unlike the other mods on this list, it only needs to be removed serverside
The available KCauldron builds on the jarlist currently does not appear to have issues with FastCraft or NotEnoughResources. MobiusCore/Opis will still cause crashes however.