diff --git a/notus/Biblioteque_de_Class/Exception.cs b/notus/Biblioteque_de_Class/Exception.cs
index a074c57..722af20 100644
--- a/notus/Biblioteque_de_Class/Exception.cs
+++ b/notus/Biblioteque_de_Class/Exception.cs
@@ -6,10 +6,16 @@ using System.Threading.Tasks;
 
 namespace Biblioteque_de_Class
 {
+    [Serializable]
     public class NotAllowedException : Exception
     {
         public NotAllowedException(string message) : base(message)
         {
+
+        }
+        protected  NotAllowedException(SerializationInfo info, StreamingContext context) : base(info, context)
+        {
+
         }
     }
     public class AlreadyUsedException : Exception
diff --git a/notus/Biblioteque_de_Class/Note.cs b/notus/Biblioteque_de_Class/Note.cs
index 216f430..efd1dba 100644
--- a/notus/Biblioteque_de_Class/Note.cs
+++ b/notus/Biblioteque_de_Class/Note.cs
@@ -102,6 +102,7 @@ namespace Biblioteque_de_Class
         {
             if (VerifyOwner(owner)) { Collaborators.Add(user); }
             else { throw new NotAllowedException("User is not the owner"); }
+            user.GetNoteList().Add(this);
         }
 
         /// <summary>
@@ -111,6 +112,7 @@ namespace Biblioteque_de_Class
         {
             if (VerifyOwner(owner)) { Collaborators.Remove(user); }
             else { throw new NotAllowedException("User is not the owner"); }
+            user.GetNoteList().Remove(this);
         }
 
         /// <summary>