diff --git a/gns3server/modules/dynamips/__init__.py b/gns3server/modules/dynamips/__init__.py
index ed6858a8..3bbeaf5a 100644
--- a/gns3server/modules/dynamips/__init__.py
+++ b/gns3server/modules/dynamips/__init__.py
@@ -208,7 +208,7 @@ class Dynamips(BaseManager):
         """
 
         # save the configs when the project is committed
-        for vm in self._vms.values():
+        for vm in self._vms.copy().values():
             if vm.project.id == project.id:
                 yield from vm.save_configs()