diff --git a/src/js/controller/login-existing.js b/src/js/controller/login-existing.js
index e206448..9acb772 100644
--- a/src/js/controller/login-existing.js
+++ b/src/js/controller/login-existing.js
@@ -4,7 +4,8 @@ define(function(require) {
     var appController = require('js/app-controller');
 
     var LoginExistingCtrl = function($scope, $location) {
-        
+        $scope.buttonEnabled = true;
+
         $scope.confirmPassphrase = function() {
             var passphrase = $scope.passphrase,
                 emailDao = appController._emailDao;
@@ -13,6 +14,8 @@ define(function(require) {
                 return;
             }
 
+            // disable button once loggin has started
+            $scope.buttonEnabled = false;
             unlockCrypto(imapLogin);
 
             function unlockCrypto(callback) {
@@ -28,6 +31,7 @@ define(function(require) {
 
             function imapLogin(err) {
                 if (err) {
+                    $scope.buttonEnabled = true;
                     console.error(err);
                     return;
                 }
@@ -35,6 +39,7 @@ define(function(require) {
                 // login to imap backend
                 appController._emailDao.imapLogin(function(err) {
                     if (err) {
+                        $scope.buttonEnabled = true;
                         console.error(err);
                         return;
                     }
@@ -50,4 +55,4 @@ define(function(require) {
     };
 
     return LoginExistingCtrl;
-});
+});
\ No newline at end of file
diff --git a/src/tpl/login-existing.html b/src/tpl/login-existing.html
index 9989c85..101171f 100644
--- a/src/tpl/login-existing.html
+++ b/src/tpl/login-existing.html
@@ -14,7 +14,7 @@
        <input type="password" ng-model="passphrase" class="passphrase" placeholder="Passphrase" tabindex="1" focus-me="true">
       </div>
       <div>
-        <button type="submit" ng-click="confirmPassphrase()" class="btn" tabindex="2">Unlock</button>
+        <button type="submit" ng-click="confirmPassphrase()" class="btn" ng-disabled="!buttonEnabled" tabindex="2">Unlock</button>
       </div>
     </form>
   </div><!--/content-->