diff --git a/openviking/service/core.py b/openviking/service/core.py
index e559698b..d025d663 100644
--- a/openviking/service/core.py
+++ b/openviking/service/core.py
@@ -245,14 +245,14 @@ async def close(self) -> None:
             self._transaction_manager.stop()
             self._transaction_manager = None
 
-        if self._agfs_manager:
-            self._agfs_manager.stop()
-            self._agfs_manager = None
-
         if self._vikingdb_manager:
             await self._vikingdb_manager.close()
             self._vikingdb_manager = None
 
+        if self._agfs_manager:
+            self._agfs_manager.stop()
+            self._agfs_manager = None
+
         self._viking_fs = None
         self._resource_processor = None
         self._skill_processor = None
diff --git a/openviking/storage/collection_schemas.py b/openviking/storage/collection_schemas.py
index 5cdb442b..1226c851 100644
--- a/openviking/storage/collection_schemas.py
+++ b/openviking/storage/collection_schemas.py
@@ -13,7 +13,7 @@
 from openviking.models.embedder.base import EmbedResult
 from openviking.storage.queuefs.embedding_msg import EmbeddingMsg
 from openviking.storage.queuefs.named_queue import DequeueHandlerBase
-from openviking.storage.vikingdb_interface import VikingDBInterface
+from openviking.storage.vikingdb_interface import CollectionNotFoundError, VikingDBInterface
 from openviking.utils import get_logger
 from openviking.utils.config.open_viking_config import OpenVikingConfig
 
@@ -165,6 +165,15 @@ async def on_dequeue(self, data: Optional[Dict[str, Any]]) -> Optional[Dict[str,
                     logger.debug(
                         f"Successfully wrote embedding to database: {record_id} abstract {inserted_data['abstract']} vector {inserted_data['vector'][:5]}"
                     )
+            except CollectionNotFoundError as db_err:
+                # During shutdown, queue workers may finish one dequeued item.
+                if getattr(self._vikingdb, "is_closing", False):
+                    logger.debug(f"Skip embedding write during shutdown: {db_err}")
+                    self.report_success()
+                    return None
+                logger.error(f"Failed to write to vector database: {db_err}")
+                self.report_error(str(db_err), data)
+                return None
             except Exception as db_err:
                 logger.error(f"Failed to write to vector database: {db_err}")
                 import traceback
diff --git a/openviking/storage/queuefs/queue_manager.py b/openviking/storage/queuefs/queue_manager.py
index 7585a1b7..35974b86 100644
--- a/openviking/storage/queuefs/queue_manager.py
+++ b/openviking/storage/queuefs/queue_manager.py
@@ -138,6 +138,7 @@ def _queue_worker_loop(self, queue: NamedQueue, stop_event: threading.Event) ->
 
     def stop(self) -> None:
         """Stop QueueManager and release resources."""
+        global _instance
         if not self._started:
             return
 
@@ -152,6 +153,10 @@ def stop(self) -> None:
         self._agfs = None
         self._queues.clear()
         self._started = False
+
+        if _instance is self:
+            _instance = None
+
         logger.info("[QueueManager] Stopped")
 
     def is_running(self) -> bool:
diff --git a/openviking/storage/vikingdb_manager.py b/openviking/storage/vikingdb_manager.py
index 59f9b8f3..3c9e8fa1 100644
--- a/openviking/storage/vikingdb_manager.py
+++ b/openviking/storage/vikingdb_manager.py
@@ -58,6 +58,7 @@ def __init__(
         self._queue_manager = None
         self._embedding_handler = None
         self._semantic_processor = None
+        self._closing = False
 
         # Initialize queue manager if AGFS URL is provided
         self._init_queue_manager()
@@ -114,8 +115,9 @@ def _init_semantic_queue(self):
 
     async def close(self) -> None:
         """Close storage connection and release resources, including queue manager."""
+        self._closing = True
         try:
-            # First stop the queue manager to prevent new operations
+            # Close should stop queue processing immediately.
             if self._queue_manager:
                 self._queue_manager.stop()
                 self._queue_manager = None
@@ -127,6 +129,11 @@ async def close(self) -> None:
         except Exception as e:
             logger.error(f"Error closing VikingDB manager: {e}")
 
+    @property
+    def is_closing(self) -> bool:
+        """Whether the manager is in shutdown flow."""
+        return self._closing
+
     # =========================================================================
     # Queue Management Properties
     # =========================================================================