diff --git a/application/api/user/routes.py b/application/api/user/routes.py
index d8a19913..da7ebe07 100644
--- a/application/api/user/routes.py
+++ b/application/api/user/routes.py
@@ -3695,35 +3695,45 @@ class UpdateChunk(Resource):
             )
         try:
             store = get_vector_store(doc_id)
+
             chunks = store.get_chunks()
             existing_chunk = next((c for c in chunks if c["doc_id"] == chunk_id), None)
             if not existing_chunk:
                 return make_response(jsonify({"error": "Chunk not found"}), 404)
-            deleted = store.delete_chunk(chunk_id)
-            if not deleted:
-                return make_response(
-                    jsonify({"error": "Failed to delete existing chunk"}), 500
-                )
+
             new_text = text if text is not None else existing_chunk["text"]
-            new_metadata = (
-                metadata if metadata is not None else existing_chunk["metadata"]
-            )
 
-            if text is not None and metadata is None:
-                token_count = num_tokens_from_string(new_text)
-                new_metadata["token_count"] = token_count
+            if metadata is not None:
+                new_metadata = existing_chunk["metadata"].copy()
+                new_metadata.update(metadata)
+            else:
+                new_metadata = existing_chunk["metadata"].copy()
 
-            new_chunk_id = store.add_chunk(new_text, new_metadata)
+            if text is not None:
+                new_metadata["token_count"] = num_tokens_from_string(new_text)
 
-            return make_response(
-                jsonify(
-                    {
-                        "message": "Chunk updated successfully",
-                        "new_chunk_id": new_chunk_id,
-                    }
-                ),
-                200,
-            )
+            try:
+                new_chunk_id = store.add_chunk(new_text, new_metadata)
+
+                deleted = store.delete_chunk(chunk_id)
+                if not deleted:
+                    current_app.logger.warning(f"Failed to delete old chunk {chunk_id}, but new chunk {new_chunk_id} was created")
+
+                return make_response(
+                    jsonify(
+                        {
+                            "message": "Chunk updated successfully",
+                            "chunk_id": new_chunk_id,
+                            "original_chunk_id": chunk_id,
+                        }
+                    ),
+                    200,
+                )
+            except Exception as add_error:
+                current_app.logger.error(f"Failed to add updated chunk: {add_error}")
+                return make_response(
+                    jsonify({"error": "Failed to update chunk - addition failed"}), 500
+                )
         except Exception as e:
             current_app.logger.error(f"Error updating chunk: {e}", exc_info=True)
             return make_response(jsonify({"success": False}), 500)
diff --git a/application/vectorstore/faiss.py b/application/vectorstore/faiss.py
index b9c63cc8..3e86203b 100644
--- a/application/vectorstore/faiss.py
+++ b/application/vectorstore/faiss.py
@@ -67,25 +67,36 @@ class FaissStore(BaseVectorStore):
     def add_texts(self, *args, **kwargs):
         return self.docsearch.add_texts(*args, **kwargs)
 
-    def save_local(self, path):
+    def _save_to_storage(self):
         """
-        Save the FAISS index to disk and upload to storage.
-        
-        Args:
-            path: Path where the index should be stored
+        Save the FAISS index to storage using temporary directory pattern.
+        Works consistently for both local and S3 storage.
         """
         with tempfile.TemporaryDirectory() as temp_dir:
             self.docsearch.save_local(temp_dir)
-            
-            with open(os.path.join(temp_dir, "index.faiss"), "rb") as f_faiss:
+
+            faiss_path = os.path.join(temp_dir, "index.faiss")
+            pkl_path = os.path.join(temp_dir, "index.pkl")
+
+            with open(faiss_path, "rb") as f_faiss:
                 faiss_data = f_faiss.read()
-            
-            with open(os.path.join(temp_dir, "index.pkl"), "rb") as f_pkl:
+
+            with open(pkl_path, "rb") as f_pkl:
                 pkl_data = f_pkl.read()
-    
-            self.storage.save_file(io.BytesIO(faiss_data), f"{path}/index.faiss")
-            self.storage.save_file(io.BytesIO(pkl_data), f"{path}/index.pkl")
-        
+
+            storage_path = get_vectorstore(self.source_id)
+            self.storage.save_file(io.BytesIO(faiss_data), f"{storage_path}/index.faiss")
+            self.storage.save_file(io.BytesIO(pkl_data), f"{storage_path}/index.pkl")
+
+        return True
+
+    def save_local(self, path=None):
+        if path:
+            os.makedirs(path, exist_ok=True)
+            self.docsearch.save_local(path)
+
+        self._save_to_storage()
+
         return True
 
     def delete_index(self, *args, **kwargs):
@@ -122,13 +133,17 @@ class FaissStore(BaseVectorStore):
         return chunks
 
     def add_chunk(self, text, metadata=None):
+        """Add a new chunk and save to storage."""
         metadata = metadata or {}
         doc = Document(text=text, extra_info=metadata).to_langchain_format()
         doc_id = self.docsearch.add_documents([doc])
-        self.save_local(self.path)
+        self._save_to_storage()
         return doc_id
 
+
+
     def delete_chunk(self, chunk_id):
+        """Delete a chunk and save to storage."""
         self.delete_index([chunk_id])
-        self.save_local(self.path)
+        self._save_to_storage()
         return True