diff --git a/UI/WebServerResources/MailerUI.js b/UI/WebServerResources/MailerUI.js
index d42e94c..ed215ad 100644
--- a/UI/WebServerResources/MailerUI.js
+++ b/UI/WebServerResources/MailerUI.js
@@ -2401,7 +2401,7 @@ function saveFoldersState() {
     if (mailAccounts.length > 0) {
         var foldersState = mailboxTree.getFoldersState();
         var urlstr =  ApplicationBaseURL + "/saveFoldersState";
-        var parameters = "expandedFolders=" + foldersState;
+        var parameters = "expandedFolders=" + jQuery.parseJSON(foldersState).join(',');
         triggerAjaxRequest(urlstr, saveFoldersStateCallback, null, parameters,
                            { "Content-type": "application/x-www-form-urlencoded" });
     }