diff --git a/meshroom/common/core.py b/meshroom/common/core.py
index 16f53f3e..766480e6 100644
--- a/meshroom/common/core.py
+++ b/meshroom/common/core.py
@@ -120,9 +120,12 @@ class CoreProperty(property):
 
 
 class CoreObject(object):
+
     def __init__(self, parent=None, *args, **kwargs):
         super(CoreObject, self).__init__()
         self._parent = parent
+        # Note: we do not use ClassSignal, as it can not be used in __del__.
+        self.destroyed = PySignal.Signal()
 
     def __del__(self):
         self.destroyed.emit()
@@ -130,8 +133,6 @@ class CoreObject(object):
     def parent(self):
         return self._parent
 
-    destroyed = PySignal.ClassSignal()
-
 
 DictModel = CoreDictModel
 ListModel = CoreListModel