diff --git a/src/Infrastructure/BotSharp.Abstraction/Conversations/ConversationHookBase.cs b/src/Infrastructure/BotSharp.Abstraction/Conversations/ConversationHookBase.cs
index 0f115d5d..a84c8693 100644
--- a/src/Infrastructure/BotSharp.Abstraction/Conversations/ConversationHookBase.cs
+++ b/src/Infrastructure/BotSharp.Abstraction/Conversations/ConversationHookBase.cs
@@ -79,6 +79,6 @@ public abstract class ConversationHookBase : IConversationHook
     public virtual Task OnNotificationGenerated(RoleDialogModel message)
         => Task.CompletedTask;
 
-    public Task OnUserDisconnected(Conversation conversation)
+    public virtual Task OnUserDisconnected(Conversation conversation)
         => Task.CompletedTask;
 }
diff --git a/src/Infrastructure/BotSharp.Core/Repository/FileRepository/FileRepository.Conversation.cs b/src/Infrastructure/BotSharp.Core/Repository/FileRepository/FileRepository.Conversation.cs
index 4e5998fb..647282a4 100644
--- a/src/Infrastructure/BotSharp.Core/Repository/FileRepository/FileRepository.Conversation.cs
+++ b/src/Infrastructure/BotSharp.Core/Repository/FileRepository/FileRepository.Conversation.cs
@@ -171,7 +171,8 @@ public partial class FileRepository
         var json = File.ReadAllText(convFile);
         var conv = JsonSerializer.Deserialize<Conversation>(json, _options);
 
-        var tags = conv.Tags.Concat(toAddTags).ToList();
+        var tags = conv.Tags ?? [];
+        tags = tags.Concat(toAddTags).Distinct().ToList();
         conv.Tags = tags.Where(x => !toDeleteTags.Contains(x, StringComparer.OrdinalIgnoreCase)).ToList();
 
         conv.UpdatedTime = DateTime.UtcNow;
diff --git a/src/Plugins/BotSharp.Plugin.MongoStorage/Repository/MongoRepository.Conversation.cs b/src/Plugins/BotSharp.Plugin.MongoStorage/Repository/MongoRepository.Conversation.cs
index 393846bf..ebae075b 100644
--- a/src/Plugins/BotSharp.Plugin.MongoStorage/Repository/MongoRepository.Conversation.cs
+++ b/src/Plugins/BotSharp.Plugin.MongoStorage/Repository/MongoRepository.Conversation.cs
@@ -142,10 +142,12 @@ public partial class MongoRepository
         var conv = _dc.Conversations.Find(filter).FirstOrDefault();
         if (conv == null) return false;
 
-
+        var tags = conv.Tags ?? [];
+        tags = tags.Concat(toAddTags).Distinct().ToList();
+        tags = tags.Where(x => !toDeleteTags.Contains(x, StringComparer.OrdinalIgnoreCase)).ToList();
 
         var update = Builders<ConversationDocument>.Update
-                                                   .Set(x => x.Tags, tags ?? new())
+                                                   .Set(x => x.Tags, tags)
                                                    .Set(x => x.UpdatedTime, DateTime.UtcNow);
 
         var res = _dc.Conversations.UpdateOne(filter, update);