diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/UiExtensionManager.java b/web/gui/src/main/java/org/onosproject/ui/impl/UiExtensionManager.java
index 3488707..ed9eead 100644
--- a/web/gui/src/main/java/org/onosproject/ui/impl/UiExtensionManager.java
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/UiExtensionManager.java
@@ -189,6 +189,7 @@
     @Deactivate
     public void deactivate() {
         prefs.removeListener(prefsListener);
+        prefs.destroy();
         UiWebSocketServlet.closeAll();
         unregister(core);
         log.info("Stopped");