Skyrim decides to ignore the facegendata\facegeom\Skyrim.esm NPC Face NIF files completely. I can make all changes to the NIF files in there but no change ingame Is there a cache I should take care of? Tried: - disabled NPC changing mod -> Loads Skyrim.ESM default head instead of 000A2C8E.NIF - no conflicting mods according to TES5Edit - cleaned Save file - copy NIF of a random NPC over Lydia's ID, she still shows up as the changes set in an ESP or default Skyrim.esm I don't think I'm a n00b modder but I'm starting to doubt everything :D Solved: I figured to post the answer to my issue in case somebody else experiences it. In the BSFaceGenNiNodeSkinned node, there is a text value with the name reference of the headpart that was used to generate this face. As all the face data is present in the NIF, I didn't think the name mattered. However, if the headpart is not found, it cannot load the .tri files and will discard the Facegen NIF and recalculate the face it according to the changes made by the ESP. After chaning the headpart reference in the NIF, it loaded again :)