diff --git a/user.js b/user.js
index 5df39f2..d1b93ae 100644
--- a/user.js
+++ b/user.js
@@ -5,6 +5,7 @@ user_pref("dom.ipc.plugins.flash.subprocess.crashreporter.enabled", false);
 // Discovery
 user_pref("browser.discovery.enabled", false);
 user_pref("browser.discovery.containers.enabled", false);
+user_pref("browser.discovery.sites", "");
 
 // Geolocation
 user_pref("geo.enabled", false);