Locate Unity Assets Which Contain Broken References

UnityUtils.cs

using System;
using System.IO;
using UnityEditor;
using UnityEngine;
using System.Linq;
using System.Threading.Tasks;

public class UnityUtils: MonoBehaviour
{
    [MenuItem("Tools/Find Broken GUIDs")]
    public static void FindBrokenGUIDs()
    {
        Task task = Task.Run(() =>
        {
            string searchText = "guid: 00000000000000000000000000000000";
            Debug.Log("Searching for '" + searchText + "'");
            Debug.Log("Scanning directory " + Environment.CurrentDirectory);
            DirectoryInfo directoryInfo = new DirectoryInfo(Environment.CurrentDirectory);
            foreach (DirectoryInfo subdirectory in directoryInfo.GetDirectories())
            {
                if (subdirectory.Name.StartsWith("."))
                    continue;
                if (subdirectory.Name == "obj")
                    continue;
                if (subdirectory.Name == "Library")
                    continue;
                if (subdirectory.Name == "Temp")
                    continue;

                string[] extensions = new string[]
                {
                    ".anim",
                    ".asset",
                    ".controller",
                    ".prefab",
                    ".mat",
                    ".meta",
                    ".terrainlayer",
                    ".unity",
                };

                var files = subdirectory.GetFiles("*", SearchOption.AllDirectories).
                    Where(a => extensions.Contains(a.Extension)).ToList();
                Debug.Log("Scanning " + files.Count + " files");

                foreach (FileInfo file in files)
                {
                    string[] lines = File.ReadAllLines(file.FullName);
                    foreach (string line in lines)
                        if (line.Contains(searchText))
                        {
                            Debug.Log("Broken Link: " + file.FullName);
                            break;
                        }
                }

                Debug.Log("Finished");

            }
        });
    }
}