diff --git a/4chan_x.js b/4chan_x.js
index 63f2d5613..c076165ad 100644
--- a/4chan_x.js
+++ b/4chan_x.js
@@ -1560,7 +1560,7 @@
   if ($.isDST()) {
     g.chanOffset -= 1;
   }
-  lastChecked = GM_getValue('lastChecked', 0);
+  lastChecked = Number(GM_getValue('lastChecked', '0'));
   now = Date.now();
   DAY = 24 * 60 * 60;
   if (lastChecked < now - 1 * DAY) {
@@ -1579,7 +1579,7 @@
     }
     GM_setValue("hiddenThreads/" + g.BOARD + "/", JSON.stringify(g.hiddenThreads));
     GM_setValue("hiddenReplies/" + g.BOARD + "/", JSON.stringify(g.hiddenReplies));
-    GM_setValue('lastChecked', now);
+    GM_setValue('lastChecked', now.toString());
   }
   GM_addStyle('\
   #iHover {\
diff --git a/script.coffee b/script.coffee
index 814c79561..2e8edb99a 100644
--- a/script.coffee
+++ b/script.coffee
@@ -1200,7 +1200,7 @@ tzOffset = (new Date()).getTimezoneOffset() / 60
 g.chanOffset = 5 - tzOffset# 4chan = EST = GMT -5
 if $.isDST() then g.chanOffset -= 1
 
-lastChecked = GM_getValue('lastChecked', 0)
+lastChecked = Number GM_getValue('lastChecked', '0')
 now = Date.now()
 DAY = 24 * 60 * 60
 if lastChecked < now - 1*DAY
@@ -1217,7 +1217,7 @@ if lastChecked < now - 1*DAY
 
   GM_setValue("hiddenThreads/#{g.BOARD}/", JSON.stringify(g.hiddenThreads))
   GM_setValue("hiddenReplies/#{g.BOARD}/", JSON.stringify(g.hiddenReplies))
-  GM_setValue('lastChecked', now)
+  GM_setValue('lastChecked', now.toString())
 
 GM_addStyle '
   #iHover {