diff --git a/PoliNetwork.Graduatorie.Common/Utils/EnrollUtil.cs b/PoliNetwork.Graduatorie.Common/Utils/EnrollUtil.cs
index a5446ec6..702efc24 100644
--- a/PoliNetwork.Graduatorie.Common/Utils/EnrollUtil.cs
+++ b/PoliNetwork.Graduatorie.Common/Utils/EnrollUtil.cs
@@ -23,13 +23,11 @@ public static EnrollType GetEnrollType(string? rowCanEnrollInto, bool rowCanEnro
 
         var s = rowCanEnrollInto.Split(sep).ToList();
         var type = s.FirstOrDefault(x => tester.Any(t => t == x.ToLower()));
-        if (type != null)
-        {
-            s.Remove(type);
-        }
+
+        if (type != null) s.Remove(type);
 
         var course = string.Join(sep, s);
-            return new EnrollType { CanEnroll = true, Course = course, Type = type };
-        
+        return new EnrollType { CanEnroll = true, Course = course, Type = type };
+
     }
 }
\ No newline at end of file
diff --git a/PoliNetwork.Graduatorie.Scraper/Utils/Web/CheckUrlUtil.cs b/PoliNetwork.Graduatorie.Scraper/Utils/Web/CheckUrlUtil.cs
new file mode 100644
index 00000000..5c9809fb
--- /dev/null
+++ b/PoliNetwork.Graduatorie.Scraper/Utils/Web/CheckUrlUtil.cs
@@ -0,0 +1,53 @@
+#region
+
+using PoliNetwork.Graduatorie.Common.Enums;
+using PoliNetwork.Graduatorie.Common.Objects.RankingNS;
+
+#endregion
+
+namespace PoliNetwork.Graduatorie.Scraper.Utils.Web;
+
+public class CheckUrlUtil
+{
+    public static void CheckUrl(RankingUrl variable, HashSet<RankingUrl> final)
+    {
+        try
+        {
+            var x = UrlUtils.CheckUrl(variable);
+            if (!x) return;
+            lock (final)
+            {
+                final.Add(variable);
+            }
+        }
+        catch (Exception exception)
+        {
+            Console.WriteLine(exception);
+        }
+    }
+
+    public static HashSet<RankingUrl> GetRankingLinks(IEnumerable<string> rankingsLinks)
+    {
+        var parallelQuery = rankingsLinks
+            .AsParallel()
+            .Select(RankingUrl.From)
+            .Where(r => r.PageEnum == PageEnum.Index).ToList();
+
+        return GetRankingLinksHashSet(parallelQuery);
+    }
+
+    public static HashSet<RankingUrl> GetRankingLinksHashSet(IEnumerable<RankingUrl> parallelQuery)
+    {
+        var final = new HashSet<RankingUrl>();
+
+        var action = parallelQuery.Select((Func<RankingUrl, Action>)Selector).ToArray();
+        Parallel.Invoke(action);
+
+        return final;
+
+        Action Selector(RankingUrl variable)
+        {
+            return () => { CheckUrl(variable, final); };
+        }
+    }
+}
\ No newline at end of file
diff --git a/PoliNetwork.Graduatorie.Scraper/Utils/Web/LinksFind.cs b/PoliNetwork.Graduatorie.Scraper/Utils/Web/LinksFind.cs
index 947ce73d..77d782ff 100644
--- a/PoliNetwork.Graduatorie.Scraper/Utils/Web/LinksFind.cs
+++ b/PoliNetwork.Graduatorie.Scraper/Utils/Web/LinksFind.cs
@@ -2,7 +2,6 @@
 
 using PoliNetwork.Core.Utils;
 using PoliNetwork.Graduatorie.Common.Data;
-using PoliNetwork.Graduatorie.Common.Enums;
 using PoliNetwork.Graduatorie.Common.Extensions;
 using PoliNetwork.Graduatorie.Common.Objects.RankingNS;
 
@@ -22,27 +21,23 @@ public static IEnumerable<RankingUrl> GetAll()
         var rankingsLinks = new HashSet<string>();
         rankingsLinks.AddRange(polimiNewsLinks, combinationLinks);
 
-        var rankingsUrls = rankingsLinks
-            .AsParallel() // from 500ms to 86ms 
-            .Select(RankingUrl.From)
-            .Where(r => r.PageEnum == PageEnum.Index)
-            .Where(UrlUtils.CheckUrl)
-            .ToHashSet();
+        var rankingsUrls = CheckUrlUtil.GetRankingLinks(rankingsLinks);
 
         var len = rankingsUrls.ToArray().Length;
         Console.WriteLine($"[INFO] LinksFind.GetAll found {len} links");
         return rankingsUrls;
     }
 
+
     private static IEnumerable<string> GetCombinationLinks()
     {
         var r = new HashSet<string>();
         var nowYear = DateTime.UtcNow.Year;
-        for (var i = 2021; i <= nowYear; i++) r.AddRange(GetYearCominationLinks(i));
+        for (var i = 2021; i <= nowYear; i++) r.AddRange(GetYearCombinationLinks(i));
         return r;
     }
 
-    private static IEnumerable<string> GetYearCominationLinks(int year)
+    private static IEnumerable<string> GetYearCombinationLinks(int year)
     {
         // partial implemented: polimi has recently added 4 hex chars in the first part 
         // of the path (2022_20064_XXXX_html/) which would require 65k combinations for each 
diff --git a/PoliNetwork.Graduatorie.Scraper/Utils/Web/ScraperOutput.cs b/PoliNetwork.Graduatorie.Scraper/Utils/Web/ScraperOutput.cs
index 3a3e768f..cf79fe07 100644
--- a/PoliNetwork.Graduatorie.Scraper/Utils/Web/ScraperOutput.cs
+++ b/PoliNetwork.Graduatorie.Scraper/Utils/Web/ScraperOutput.cs
@@ -66,7 +66,7 @@ public static void Write(List<RankingUrl> rankingsUrls, string? dataFolder)
     private static string GetOutputLinksString(IEnumerable<RankingUrl> rankingsUrls)
     {
         var output = "";
-        var urls = rankingsUrls.Where(UrlUtils.CheckUrl).Select(x => x.Url).Order();
+        var urls = CheckUrlUtil.GetRankingLinksHashSet(rankingsUrls).Order();
         foreach (var link in urls)
         {
             output += link;
diff --git a/PoliNetwork.Graduatorie.Scraper/Utils/Web/UrlUtils.cs b/PoliNetwork.Graduatorie.Scraper/Utils/Web/UrlUtils.cs
index 1e3eb03b..e54ea691 100644
--- a/PoliNetwork.Graduatorie.Scraper/Utils/Web/UrlUtils.cs
+++ b/PoliNetwork.Graduatorie.Scraper/Utils/Web/UrlUtils.cs
@@ -23,13 +23,15 @@ public static string UrlifyLocalHref(string href, string? domain)
 
     public static bool CheckUrl(RankingUrl? url)
     {
-        if (string.IsNullOrEmpty(url?.Url))
+        var urlUrl = url?.Url;
+        if (string.IsNullOrEmpty(urlUrl))
             return false;
 
         using var client = new HttpClient();
         try
         {
-            var response = client.GetAsync(url.Url).Result;
+            var async = client.GetAsync(urlUrl);
+            var response = async.Result;
             return response.StatusCode == HttpStatusCode.OK;
         }
         catch (HttpRequestException)