diff --git a/meshroom/ui/reconstruction.py b/meshroom/ui/reconstruction.py
index ee87a710..9706732f 100755
--- a/meshroom/ui/reconstruction.py
+++ b/meshroom/ui/reconstruction.py
@@ -213,7 +213,8 @@ class ViewpointWrapper(QObject):
         else:
             self._initialIntrinsics = self._reconstruction.getIntrinsic(self._viewpoint)
             try:
-                self._metadata = json.loads(self._viewpoint.metadata.value) if self._viewpoint.metadata.value else None
+                # When the viewpoint attribute has already been deleted, metadata.value becomes a PySide property (whereas a string is expected)
+                self._metadata = json.loads(self._viewpoint.metadata.value) if isinstance(self._viewpoint.metadata.value, str) and self._viewpoint.metadata.value else None
             except Exception as e:
                 logging.warning("Failed to parse Viewpoint metadata: '{}', '{}'".format(str(e), str(self._viewpoint.metadata.value)))
                 self._metadata = {}