diff --git a/gns3server/schemas/dynamips_vm.py b/gns3server/schemas/dynamips_vm.py
index 8cb03c9b..f91712ad 100644
--- a/gns3server/schemas/dynamips_vm.py
+++ b/gns3server/schemas/dynamips_vm.py
@@ -33,7 +33,7 @@ VM_CREATE_SCHEMA = {
         },
         "dynamips_id": {
             "description": "Dynamips ID",
-            "type": "integer"
+            "type": ["integer", "null"]
         },
         "name": {
             "description": "Dynamips VM instance name",