Non-streamed actor (IsSpatiallyLoaded=false) /ObstacleTycoon/UEFN_Tycoon.Ytycoonbutton5 references Streamed actor (IsSpatiallyLoaded=true) /ObstacleTycoon/UEFN_Tycoon.Prop_ButtonUFODetailed6 . Content or devices not marked for streaming cannot reference streamed content or devices. Either remove the reference to streamed content or mark the referenced content as non-streaming