我遇到这个问题的情况是， 在Start()中直接使用WWW价值本地图片，可能是加载图片相对比较耗时，就出现了这个错误。

解决的办法是使用协程:

// Use this for initialization	void Start () {		AddSampleData ();		}	void AddSampleData(){	StartCoroutine(WaitLoadImage("/Users/xxxx/xxx/xxx.jpg", go));	}	IEnumerator WaitLoadImage(string fileName, GameObject targetGameObject)	{		RectTransform rectTransform = targetGameObject.GetComponent
     
       ();		WWW www=new WWW("file://"+fileName);		Image img = targetGameObject.GetComponent
       ();		Debug.Log(www.url);		yield return www;		Rect spriteRect = new Rect (0, 0, www.texture.width, www.texture.height);		Sprite imageSprite = Sprite.Create (www.texture, spriteRect, new Vector2 (0.5f, 0.5f));		img.sprite = imageSprite;	}