diff --git a/common/modules/storage.jsm b/common/modules/storage.jsm
index 88fb7e52..4af8d929 100644
--- a/common/modules/storage.jsm
+++ b/common/modules/storage.jsm
@@ -327,7 +327,8 @@ var File = Class("File", {
      */
     child: function (name) {
         let f = this.constructor(this);
-        f.QueryInterface(Ci.nsILocalFile).appendRelativePath(name);
+        for each (let elem in name.split(File.pathSplit))
+            f.append(elem);
         return f;
     },
 
@@ -503,6 +504,8 @@ var File = Class("File", {
         return f.path.substr(f.parent.path.length, 1);
     }),
 
+    pathSplit: Class.memoize(function () util.regexp("(?:/|" + util.regexp.escape(this.PATH_SEP) + ")", "g")),
+
     DoesNotExist: function (path, error) ({
         path: path,
         exists: function () false,