diff --git a/tools/python/xen/xm/main.py b/tools/python/xen/xm/main.py
index e1053e4e0b..1e0d8502e4 100644
--- a/tools/python/xen/xm/main.py
+++ b/tools/python/xen/xm/main.py
@@ -567,6 +567,8 @@ def get_single_vm(dom):
         if len(uuids) > 0:
             return uuids[0]
 
+        refs = []
+
         try:
             domid = int(dom)
             refs = [vm_ref