diff --git a/CIME/XML/machines.py b/CIME/XML/machines.py
index e3a047d25de..b5c10332acb 100644
--- a/CIME/XML/machines.py
+++ b/CIME/XML/machines.py
@@ -263,6 +263,7 @@ def _probe_machine_name_one_guess_v3(self, nametomatch):
 
         children = [y for x in nodes for y in self.get_children(root=x)]
 
+        machine = None
         for child in children:
             machtocheck = self.get(child, "MACH")
             regex_str = self.text(child)