diff --git a/lib/handlers/session.js b/lib/handlers/session.js
index <HASH>..<HASH> 100644
--- a/lib/handlers/session.js
+++ b/lib/handlers/session.js
@@ -115,6 +115,14 @@ module.exports = Observable.extend({
       email: req.param('email', '')
     }, _this = this;
 
+    if (req.user) {
+      return this.respond(res, 400, {
+        ok: false,
+        message: 'Too late I\'m afraid, that username is taken.',
+        step: '2.3'
+      });
+    }
+
     if (!params.name || !params.key) {
       return res.json(400, {ok: false, error: 'Missing username or password'});
     }
Checking for existence of username before creating account