diff --git a/src/pydase/data_service/abstract_data_service.py b/src/pydase/data_service/abstract_data_service.py
index f84b29e..3ce52c8 100644
--- a/src/pydase/data_service/abstract_data_service.py
+++ b/src/pydase/data_service/abstract_data_service.py
@@ -1,8 +1,7 @@
 from __future__ import annotations
 
 from abc import ABC
-from pathlib import Path
-from typing import TYPE_CHECKING, Any, Optional
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from pydase.data_service.callback_manager import CallbackManager
@@ -15,4 +14,3 @@ class AbstractDataService(ABC):
     _task_manager: TaskManager
     _callback_manager: CallbackManager
     _autostart_tasks: dict[str, tuple[Any]]
-    _filename: Optional[str | Path]
diff --git a/src/pydase/data_service/data_service.py b/src/pydase/data_service/data_service.py
index a51aa97..ec19e8d 100644
--- a/src/pydase/data_service/data_service.py
+++ b/src/pydase/data_service/data_service.py
@@ -41,7 +41,6 @@ def process_callable_attribute(attr: Any, args: dict[str, Any]) -> Any:
 
 class DataService(rpyc.Service, AbstractDataService):
     def __init__(self, **kwargs: Any) -> None:
-        self._filename: Optional[str | Path] = None
         self._callback_manager: CallbackManager = CallbackManager(self)
         self._task_manager = TaskManager(self)
 
@@ -60,7 +59,7 @@ class DataService(rpyc.Service, AbstractDataService):
                 DeprecationWarning,
                 stacklevel=2,
             )
-            self._filename = filename
+            self._filename: str | Path = filename
 
         self._callback_manager.register_callbacks()
         self.__check_instance_classes()
diff --git a/src/pydase/data_service/state_manager.py b/src/pydase/data_service/state_manager.py
index ffc15fa..8b6df90 100644
--- a/src/pydase/data_service/state_manager.py
+++ b/src/pydase/data_service/state_manager.py
@@ -58,7 +58,7 @@ class StateManager:
     """
 
     def __init__(self, service: "DataService", filename: Optional[str | Path] = None):
-        self.filename = service._filename
+        self.filename = getattr(service, "_filename", None)
 
         if filename is not None:
             if self.filename is not None:
diff --git a/src/pydase/server/server.py b/src/pydase/server/server.py
index b5b2bc4..8f745c1 100644
--- a/src/pydase/server/server.py
+++ b/src/pydase/server/server.py
@@ -204,7 +204,7 @@ class Server:
             **kwargs,
         }
         self._state_manager = StateManager(self._service, filename)
-        if self._service._filename is not None:
+        if getattr(self._service, "_filename", None) is not None:
             self._service._state_manager = self._state_manager
         self._state_manager.load_state()