playerprefs spawning errors.

In my game I use playerprefs to keep track of what level ive reached, but its impossible to run because the same error is spawned every frame. It looks like this:

I have no clue what this means or how to fix it. If anybody can shed some light on this then it would be a life-saver. I will also put the script here just in case you see an actual error.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.SceneManagement;
 
 public class body : MonoBehaviour {
 
     public Text WinText;
     public Text ScoreText;
     public Image Shield1;
     public Image Shield2;
     public AudioSource CoinSound;
    public int Score = PlayerPrefs.GetInt("Score", 0);
     public int Scene;
     public int LevelToUnlock;
     public int LevelReached = PlayerPrefs.GetInt("levelReached", 1);
     public int Health = PlayerPrefs.GetInt("Health", 1);
     public Button[] levelButtons;
     public Text[] ButtonTexts;
     public int NextLevel;
 
      //Use this for initialization
     void Start () {
 
         LevelReached = PlayerPrefs.GetInt("levelReached");
 
         Debug.Log("playerPref says " + PlayerPrefs.GetInt("levelReached"));
         Debug.Log("editor says " + LevelReached);
 
         Debug.Log("1");
 
        for (int i = 0; i < levelButtons.Length; i++)
         {
             Debug.Log("2");
 
             LevelReached = PlayerPrefs.GetInt("levelReached");
 
             if (i + 1 > LevelReached)
            {
                 Debug.Log("3");
 
                 levelButtons[i].enabled = false;
                 ButtonTexts[i].enabled = false;
 
                 Debug.Log("4");
            }
         }
 
         Health = PlayerPrefs.GetInt("Health", 1);
 
         if (Health < 2)
         {
             Shield1.enabled = false;
         }
        if (Health < 3)
         {
             Shield2.enabled = false;
         }
 
         LevelReached = PlayerPrefs.GetInt("levelReached");
 
         for (int i = 0; i > levelButtons.Length; i++)
         {
             LevelReached = PlayerPrefs.GetInt("levelReached");
 
             if (i + 1 > LevelReached)
             {
                 levelButtons[i].enabled = false;
                 ButtonTexts[i].enabled = false;
             }
         }
 
     }
     
     // Update is called once per frame
     void Update () {
 
         Score = PlayerPrefs.GetInt("Score");
 
         ScoreText.text = "Score: " + Score;
         if (Health < 2)
         {
             Shield1.enabled = false;
         }
         if (Health < 3)
         {
             Shield2.enabled = false;
         }
     }
 
     void OnTriggerEnter2D(Collider2D other)
     {
         if (other.CompareTag("Enemy"))
         {
             PlayerPrefs.SetInt("Health", PlayerPrefs.GetInt("Health") - 1);
             Health = PlayerPrefs.GetInt("Health");
     
             if (Health == 0)
             {
                 PlayerPrefs.SetInt("Health", 1);
                Health = PlayerPrefs.GetInt("Health");
                 SceneManager.LoadScene(Scene);
             }
         }
 
         if (other.CompareTag("Finish"))
         {
             StartCoroutine(Finish());
         }
 
         if (other.CompareTag("Coin"))
         {
             CoinSound.Play();
             PlayerPrefs.SetInt("Score", PlayerPrefs.GetInt("Score") + 10);
        }
     }
 
    IEnumerator Finish()
     {
         Debug.Log("Level Won!");
 
         WinText.enabled = true;
 
         if (LevelReached < LevelToUnlock)
         {
             PlayerPrefs.SetInt("levelReached", PlayerPrefs.GetInt("levelReached") + 1);
         }
     
        yield return new WaitForSeconds(3f);
 
         SceneManager.LoadScene(NextLevel);
    }
 }