diff --git a/playbook.destructor.yml b/playbook.destructor.yml
index 5c29f2f2..ee2e9a57 100644
--- a/playbook.destructor.yml
+++ b/playbook.destructor.yml
@@ -3,4 +3,4 @@
   become: true
   roles:
     - role: system-storage-optimizer
-      when: (path_mass_storage or path_rapid_storage) and enable_system_storage_optimizer | bool
\ No newline at end of file
+      when: "(path_mass_storage is defined or path_rapid_storage is defined) and enable_system_storage_optimizer | bool"