Just had this. To fix it head over to your Material/MasterMaterial and look for the TextureSample giving you the error and change the Sampler Type from (for example) Color to Virtual Color or Normal to Virtual Color and so on.
Just had this. To fix it head over to your Material/MasterMaterial and look for the TextureSample giving you the error and change the Sampler Type from (for example) Color to Virtual Color or Normal to Virtual Color and so on.