diff --git a/4chan_x.user.js b/4chan_x.user.js
index 43bb9b55d..18ea61cd5 100644
--- a/4chan_x.user.js
+++ b/4chan_x.user.js
@@ -1067,7 +1067,7 @@
     sync: function() {
       var hiddenThreads, hiddenThreadsCatalog, id;
       hiddenThreads = $.get("hiddenThreads/" + g.BOARD + "/", {});
-      hiddenThreadsCatalog = JSON.parse(localStorage.getItem("4chan-hide-t-" + g.BOARD));
+      hiddenThreadsCatalog = JSON.parse(localStorage.getItem("4chan-hide-t-" + g.BOARD)) || {};
       if (g.CATALOG) {
         for (id in hiddenThreads) {
           hiddenThreadsCatalog[id] = true;
diff --git a/script.coffee b/script.coffee
index 4bda85f94..5a49378a0 100644
--- a/script.coffee
+++ b/script.coffee
@@ -850,7 +850,7 @@ ThreadHiding =
 
   sync: ->
     hiddenThreads = $.get "hiddenThreads/#{g.BOARD}/", {}
-    hiddenThreadsCatalog = JSON.parse localStorage.getItem "4chan-hide-t-#{g.BOARD}"
+    hiddenThreadsCatalog = JSON.parse(localStorage.getItem "4chan-hide-t-#{g.BOARD}") or {}
     if g.CATALOG
       for id of hiddenThreads
         hiddenThreadsCatalog[id] = true