diff --git a/src/lib/Hydra/Controller/Root.pm b/src/lib/Hydra/Controller/Root.pm
index cbdba121..9ca2c81a 100644
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -24,6 +24,7 @@ sub begin :Private {
     $c->stash->{tracker} = $ENV{"HYDRA_TRACKER"};
     $c->stash->{flashMsg} = $c->flash->{flashMsg};
     $c->stash->{successMsg} = $c->flash->{successMsg};
+    $c->stash->{personaEnabled} = $c->config->{enable_persona} // "0" eq "1";
 
     if (scalar(@args) == 0 || $args[0] ne "static") {
         $c->stash->{nrRunningBuilds} = $c->model('DB::Builds')->search({ finished => 0, busy => 1 }, {})->count();
diff --git a/src/lib/Hydra/Controller/User.pm b/src/lib/Hydra/Controller/User.pm
index 66b645b2..024ddd2f 100644
--- a/src/lib/Hydra/Controller/User.pm
+++ b/src/lib/Hydra/Controller/User.pm
@@ -48,6 +48,8 @@ sub persona_login :Path('/persona-login') Args(0) {
     my ($self, $c) = @_;
     requirePost($c);
 
+    error($c, "Persona support is not enabled.") unless $c->stash->{personaEnabled};
+
     my $assertion = $c->req->params->{assertion} or die;
 
     my $ua = new LWP::UserAgent;
diff --git a/src/root/layout.tt b/src/root/layout.tt
index 074e4809..933fe893 100644
--- a/src/root/layout.tt
+++ b/src/root/layout.tt
@@ -101,11 +101,13 @@
 
     <script>
       function doLogout() {
-        $.post("[% c.uri_for('/logout') %]")
-          .done(function(data) {
-            window.location.reload();
-          })
-          .fail(function() { bootbox.alert("Server request failed!"); });
+        [% IF c.user_exists %]
+          $.post("[% c.uri_for('/logout') %]")
+            .done(function(data) {
+              window.location.reload();
+            })
+            .fail(function() { bootbox.alert("Server request failed!"); });
+        [% END %]
       }
     </script>
 
@@ -124,7 +126,8 @@
               url: "[% c.uri_for('/persona-login') %]",
               data: "assertion=" + assertion,
               type: 'POST',
-              success: function(data) { window.location.reload(); }
+              success: function(data) { window.location.reload(); },
+              postError: function() { navigator.id.logout(); }
             });
           },
           onlogout: doLogout
diff --git a/src/root/static/css/hydra.css b/src/root/static/css/hydra.css
index b369f3e0..6f65c649 100644
--- a/src/root/static/css/hydra.css
+++ b/src/root/static/css/hydra.css
@@ -107,4 +107,4 @@ td.nowrap {
 
 .star:hover {
     cursor: pointer;
-}
\ No newline at end of file
+}
diff --git a/src/root/static/js/common.js b/src/root/static/js/common.js
index 784c2ed3..68a65d2a 100644
--- a/src/root/static/js/common.js
+++ b/src/root/static/js/common.js
@@ -135,6 +135,7 @@ function requestJSON(args) {
             bootbox.alert("Server error: " + escapeHTML(data.responseText));
         else
             bootbox.alert("Unknown server error!");
+        if (args.postError) args.postError(data);
     };
     return $.ajax(args);
 };
diff --git a/src/root/topbar.tt b/src/root/topbar.tt
index 80895e67..6e3cd264 100644
--- a/src/root/topbar.tt
+++ b/src/root/topbar.tt
@@ -123,15 +123,21 @@
       <a href="#" id="persona-signout">Sign out</a>
     </li>
   [% ELSE %]
-    [% WRAPPER makeSubMenu title="Sign in" %]
+    [% IF personaEnabled %]
+      [% WRAPPER makeSubMenu title="Sign in" %]
+        <li>
+          <a href="#" id="persona-signin">
+            <img src="https://developer.mozilla.org/files/3963/persona_sign_in_blue.png" alt="Sign in with Persona" />
+          </a>
+        </li>
+        <li class="divider"></li>
+        <li>
+          <a href="#hydra-signin" data-toggle="modal">Sign in with a Hydra account</a>
+        </li>
+      [% END %]
+    [% ELSE %]
       <li>
-        <a href="#" id="persona-signin">
-          <img src="https://developer.mozilla.org/files/3963/persona_sign_in_blue.png" alt="Sign in with Persona" />
-        </a>
-      </li>
-      <li class="divider"></li>
-      <li>
-        <a href="#hydra-signin" data-toggle="modal">Sign in with a Hydra account</a>
+        <a href="#hydra-signin" data-toggle="modal">Sign in</a>
       </li>
     [% END %]
   [% END %]