diff --git a/lang/en.yml b/lang/en.yml
index 64a8f74e9..edb74047a 100644
--- a/lang/en.yml
+++ b/lang/en.yml
@@ -1,6 +1,4 @@
 en:
-  SilverStripe\Admin\LeftAndMain:
-    VersionUnknown: unknown
   SilverStripe\AssetAdmin\Forms\UploadField:
     Dimensions: Dimensions
     EDIT: Edit
diff --git a/src/Dev/Install/Installer.php b/src/Dev/Install/Installer.php
index 056c1c4fa..4806c3299 100644
--- a/src/Dev/Install/Installer.php
+++ b/src/Dev/Install/Installer.php
@@ -150,7 +150,7 @@ PHP
             $adminMember = DefaultAdminService::singleton()
                 ->findOrCreateAdmin(
                     $username,
-                    _t(DefaultAdminService::class . '.DefaultAdminFirstname', 'Default Admin')
+                    _t('SilverStripe\\Security\\DefaultAdminService.DefaultAdminFirstname', 'Default Admin')
                 );
             $adminMember->Email = $username;
             $adminMember->Password = $password;