Blender to Unity: Messed up material textures in Unity after joining all mesh together in Blender

So I’ve made a model in Blender and it looks fine even after I join all mesh back together, but when I import the model to Unity and put all textures on their right places on materials they still look all messed up for example a tanktop on my model becomes golden when it’s supposed to be white, the golden textures belongs to necklace… I realized it must the problem with Blender after I tried exporting the model without joining all meshes together and it looked fine in Unity after. So what’s the deal with Mesh material textures when I join all mesh Blender??? I don’t get it. I tried to recalculate normals for the entire mesh of my model, that still didn’t work.

From your description I’m 99% sure this is a problem with your material setup/assigning, or your UV’s, not a Blender problem. It would be best if you’d post the file with all resources packed on the forum and let others look at the models/materials.

I’ve found out already that I have to manually replace materials in Unity for the model. Thank you so much for your answer, I’ll consider it the next time I make a model.