diff --git a/modules/menu/menu.admin.inc b/modules/menu/menu.admin.inc
index 2d7c61ac7b8f0ed82034056c5c1eb412c739e1b9..79d3405f7306f5cc8a154a92d2b3c6dcb0afab3a 100644
--- a/modules/menu/menu.admin.inc
+++ b/modules/menu/menu.admin.inc
@@ -539,10 +539,11 @@ function menu_edit_menu_validate($form, &$form_state) {
   if (preg_match('/[^a-z0-9-]/', $item['menu_name'])) {
     form_set_error('menu_name', t('The menu name may only consist of lowercase letters, numbers, and hyphens.'));
   }
-  if (strlen($item['menu_name']) > MENU_MAX_MENU_NAME_LENGTH_UI) {
-    form_set_error('menu_name', format_plural(MENU_MAX_MENU_NAME_LENGTH_UI, "The menu name can't be longer than 1 character.", "The menu name can't be longer than @count characters."));
-  }
   if ($form['#insert']) {
+    if (strlen($item['menu_name']) > MENU_MAX_MENU_NAME_LENGTH_UI) {
+      form_set_error('menu_name', format_plural(MENU_MAX_MENU_NAME_LENGTH_UI, "The menu name can't be longer than 1 character.", "The menu name can't be longer than @count characters."));
+    }
+
     // We will add 'menu-' to the menu name to help avoid name-space conflicts.
     $item['menu_name'] = 'menu-' . $item['menu_name'];
     $custom_exists = db_query('SELECT menu_name FROM {menu_custom} WHERE menu_name = :menu', array(':menu' => $item['menu_name']))->fetchField();
diff --git a/modules/menu/menu.test b/modules/menu/menu.test
index 284f555413b3630a94a1783bc8fa63f68e4ca90a..2b00b9798ce97d5346e110701f4ba0db889500a3 100644
--- a/modules/menu/menu.test
+++ b/modules/menu/menu.test
@@ -95,8 +95,10 @@ class MenuTestCase extends DrupalWebTestCase {
    */
   function addCustomMenu() {
     // Add custom menu.
+
+    // Try adding a menu using a menu_name that is too long.
     $this->drupalGet('admin/build/menu/add');
-    $menu_name = substr(md5($this->randomName(16)), 0, 20);
+    $menu_name = substr(md5($this->randomName(16)), 0, MENU_MAX_MENU_NAME_LENGTH_UI + 1);
     $title = $this->randomName(16);
     $edit = array (
       'menu_name' => $menu_name,
@@ -104,6 +106,17 @@ class MenuTestCase extends DrupalWebTestCase {
       'title' =>  $title,
     );
     $this->drupalPost('admin/build/menu/add', $edit, t('Save'));
+
+    // Verify that using a menu_name that is too long results in a validation message.
+    $this->assertText(format_plural(MENU_MAX_MENU_NAME_LENGTH_UI, "The menu name can't be longer than 1 character.", "The menu name can't be longer than @count characters."), t('Validation failed when menu name is too long.'));
+
+    // Change the menu_name so it no longer exceeds the maximum length.
+    $menu_name = substr(md5($this->randomName(16)), 0, MENU_MAX_MENU_NAME_LENGTH_UI);
+    $edit['menu_name'] = $menu_name;
+    $this->drupalPost('admin/build/menu/add', $edit, t('Save'));
+
+    // Verify that no validation error is given for menu_name length.
+    $this->assertNoText(format_plural(MENU_MAX_MENU_NAME_LENGTH_UI, "The menu name can't be longer than 1 character.", "The menu name can't be longer than @count characters."), t('Validation failed when menu name is too long.'));
     // Unlike most other modules, there is no confirmation message displayed.
 
     $this->drupalGet('admin/build/menu');