diff --git a/meshroom/core/attribute.py b/meshroom/core/attribute.py
index b84e98d7de..82d6244d03 100644
--- a/meshroom/core/attribute.py
+++ b/meshroom/core/attribute.py
@@ -73,11 +73,8 @@ def __init__(self, node, attributeDesc, isOutput, root=None, parent=None):
         # invalidation value for output attributes
         self._invalidationValue = ""
 
-        self._value = None
         self.initValue()
 
-        self.valueChanged.connect(self.onChanged)
-
     @property
     def node(self):
         return self._node()
@@ -259,6 +256,7 @@ def upgradeValue(self, exportedValue):
     def initValue(self):
         if self.desc._valueType is not None:
             self._value = self.desc._valueType()
+        self.valueChanged.connect(self.onChanged)
 
     def resetToDefaultValue(self, emitSignals=True):
         self._set_value(copy.copy(self.defaultValue()), emitSignals=emitSignals)