diff --git a/src/aiidalab_qe/app/result/__init__.py b/src/aiidalab_qe/app/result/__init__.py
index ee6944c67..d11251285 100644
--- a/src/aiidalab_qe/app/result/__init__.py
+++ b/src/aiidalab_qe/app/result/__init__.py
@@ -154,7 +154,7 @@ def _on_kill_button_click(self, _):
 
     def _on_update_results_button_click(self, _):
         self.node_view.node = None
-        self.node_view.node = self._model.process_node
+        self.node_view.node = self._model.get_process_node()
 
     def _on_clean_scratch_button_click(self, _):
         self._model.clean_remote_data()
@@ -164,9 +164,9 @@ def _update_kill_button_layout(self):
         if not self.rendered:
             return
         if (
-            not self._model.process
-            or self._model.process_node.is_finished
-            or self._model.process_node.is_excepted
+            not (process_node := self._model.get_process_node())
+            or process_node.is_finished
+            or process_node.is_excepted
             or self.state
             in (
                 self.State.SUCCESS,
@@ -180,15 +180,16 @@ def _update_kill_button_layout(self):
     def _update_clean_scratch_button_layout(self):
         if not self.rendered:
             return
-        if self._model.process and self._model.process_node.is_terminated:
+        process_node = self._model.get_process_node()
+        if process_node and process_node.is_terminated:
             self.clean_scratch_button.layout.display = "block"
         else:
             self.clean_scratch_button.layout.display = "none"
 
     def _update_state(self):
-        if not self._model.process:
+        if not (process_node := self._model.get_process_node()):
             self.state = self.State.INIT
-        elif self._model.process_node.process_state in (
+        elif process_node.process_state in (
             ProcessState.CREATED,
             ProcessState.RUNNING,
             ProcessState.WAITING,
@@ -196,15 +197,15 @@ def _update_state(self):
             self.state = self.State.ACTIVE
             self._model.process_info = PROCESS_RUNNING
         elif (
-            self._model.process_node.process_state
+            process_node.process_state
             in (
                 ProcessState.EXCEPTED,
                 ProcessState.KILLED,
             )
-            or self._model.process_node.is_failed
+            or process_node.is_failed
         ):
             self.state = self.State.FAIL
             self._model.process_info = PROCESS_EXCEPTED
-        elif self._model.process_node.is_finished_ok:
+        elif process_node.is_finished_ok:
             self.state = self.State.SUCCESS
             self._model.process_info = PROCESS_COMPLETED
diff --git a/src/aiidalab_qe/app/result/model.py b/src/aiidalab_qe/app/result/model.py
index cf17632ca..72af4dc52 100644
--- a/src/aiidalab_qe/app/result/model.py
+++ b/src/aiidalab_qe/app/result/model.py
@@ -5,6 +5,7 @@
 import traitlets as tl
 
 from aiida import orm
+from aiida.common.exceptions import NotExistent
 from aiida.engine.processes import control
 
 
@@ -14,25 +15,27 @@ class ResultsModel(tl.HasTraits):
     process_info = tl.Unicode("")
     process_remote_folder_is_clean = tl.Bool(False)
 
-    _process_node: orm.ProcessNode | None = None
-
     @property
     def process_node(self):
-        if self._process_node is None:
-            self._process_node = self._get_process_node()
-        return self._process_node
+        return self.get_process_node()
 
     def update(self):
         self._update_process_remote_folder_state()
 
+    def get_process_node(self):
+        try:
+            return orm.load_node(self.process) if self.process else None
+        except NotExistent:
+            return None
+
     def kill_process(self):
-        if process := self._get_process_node():
-            control.kill_processes([process])
+        if process_node := self.get_process_node():
+            control.kill_processes([process_node])
 
     def clean_remote_data(self):
-        if self.process_node is None:
+        if not (process_node := self.get_process_node()):
             return
-        for called_descendant in self.process_node.called_descendants:
+        for called_descendant in process_node.called_descendants:
             if isinstance(called_descendant, orm.CalcJobNode):
                 with contextlib.suppress(Exception):
                     called_descendant.outputs.remote_folder._clean()
@@ -42,14 +45,11 @@ def reset(self):
         self.process = None
         self.process_info = ""
 
-    def _get_process_node(self):
-        return orm.load_node(self.process) if self.process else None
-
     def _update_process_remote_folder_state(self):
-        if self.process_node is None:
+        if not (process_node := self.get_process_node()):
             return
         cleaned = []
-        for called_descendant in self.process_node.called_descendants:
+        for called_descendant in process_node.called_descendants:
             if isinstance(called_descendant, orm.CalcJobNode):
                 with contextlib.suppress(Exception):
                     cleaned.append(called_descendant.outputs.remote_folder.is_empty)