diff --git a/proxy/init-badge.js b/proxy/init-badge.js
index 30c0218..09579e6 100644
--- a/proxy/init-badge.js
+++ b/proxy/init-badge.js
@@ -63,14 +63,18 @@ var snowflake, query, debug, silenceNotifications, log, dbg, init;
 
   // Notification of closing tab with active proxy.
   window.onbeforeunload = function() {
-    if (!silenceNotifications && Snowflake.MODE.WEBRTC_READY === snowflake.state) {
+    if (
+      !silenceNotifications &&
+      snowflake !== null &&
+      Snowflake.MODE.WEBRTC_READY === snowflake.state
+    ) {
       return Snowflake.MESSAGE.CONFIRMATION;
     }
     return null;
   };
 
   window.onunload = function() {
-    snowflake.disable();
+    if (snowflake !== null) { snowflake.disable(); }
     return null;
   };
 
diff --git a/proxy/init-webext.js b/proxy/init-webext.js
index 3a2b120..ee755c6 100644
--- a/proxy/init-webext.js
+++ b/proxy/init-webext.js
@@ -61,14 +61,18 @@ var debug, snowflake, config, broker, ui, log, dbg, init, update, silenceNotific
 
   // Notification of closing tab with active proxy.
   window.onbeforeunload = function() {
-    if (!silenceNotifications && Snowflake.MODE.WEBRTC_READY === snowflake.state) {
+    if (
+      !silenceNotifications &&
+      snowflake !== null &&
+      Snowflake.MODE.WEBRTC_READY === snowflake.state
+    ) {
       return Snowflake.MESSAGE.CONFIRMATION;
     }
     return null;
   };
 
   window.onunload = function() {
-    snowflake.disable();
+    if (snowflake !== null) { snowflake.disable(); }
     return null;
   };