diff --git a/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js b/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
index 73f102536926..f802e0ef2103 100644
--- a/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
+++ b/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
@@ -185,6 +185,8 @@ function HashCompleter() {
 
   Services.obs.addObserver(this, "quit-application");
   Services.prefs.addObserver(PREF_DEBUG_ENABLED, this);
+
+  loggingEnabled = Services.prefs.getBoolPref(PREF_DEBUG_ENABLED);
 }
 
 HashCompleter.prototype = {