diff --git a/nixos/lib/test-driver/src/test_driver/machine/__init__.py b/nixos/lib/test-driver/src/test_driver/machine/__init__.py
index 3dc4f1f8d171..17f19f5d3068 100644
--- a/nixos/lib/test-driver/src/test_driver/machine/__init__.py
+++ b/nixos/lib/test-driver/src/test_driver/machine/__init__.py
@@ -1721,6 +1721,7 @@ class NspawnMachine(BaseMachine):
         with self.nested("waiting for the container to power off"):
             self.process.wait()
             self.process = None
+            self.pid = None
 
 
 class MachineDeprecationWrapper: