"GameObject.FindWithTag" Working with one scene but not another

Hi guys,

I feel something strange is happening in one of my projects, I have this code bellow that works on one scene but not another, the one it doesn’t work in is my main scene (and yes I have both tags). I’m not sure quite what to do, or if i’m doing something wrong, I have tried rolling multiplier in one room so that might be it, any suggestions please help.

using UnityEngine;
using System.Collections;

public class testytest : MonoBehaviour {
	public GameObject map;
	// Use this for initialization
	void Start () {
		map = GameObject.FindWithTag("Map");
	}
	
	// Update is called once per frame
	void Update () {
		
	}
}

I may be mistaken but isn’t it

map = GameObject.FindGameObjectWithTag("Map");

even so, I prefer to use layers. String methods as above are not suggested for performance