diff --git a/lib/Alchemy/Phrasea/Setup/Version/MailChecker.php b/lib/Alchemy/Phrasea/Setup/Version/MailChecker.php
index 9cea69a9a6..350506be3e 100644
--- a/lib/Alchemy/Phrasea/Setup/Version/MailChecker.php
+++ b/lib/Alchemy/Phrasea/Setup/Version/MailChecker.php
@@ -12,7 +12,7 @@
 namespace Alchemy\Phrasea\Setup\Version;
 
 use Alchemy\Phrasea\Application;
-use Alchemy\Phrasea\Core\Version;
+use Doctrine\DBAL\Driver\Statement;
 
 /**
  * In version 3.9 the user table have been removed.
@@ -21,23 +21,42 @@ use Alchemy\Phrasea\Core\Version;
  */
 class MailChecker
 {
+    /** @var \appbox */
+    private $appbox;
+    /** @var string */
+    private $table;
+
+    /**
+     * Constructor
+     *
+     * @param \appbox $appbox
+     * @param string  $table
+     */
+    public function __construct(\appbox $appbox, $table = 'usr')
+    {
+        $this->appbox = $appbox;
+        $this->table = $table;
+    }
+
     /**
      * Returns users with duplicated emails
      *
-     * @param \Application $app
-     * @param string       $table The table name where to look
-     *
      * @return array An array of User
      */
-    public static function getWrongEmailUsers(Application $app, $table = 'usr')
+    public function getWrongEmailUsers()
     {
-        if (version_compare(Version::getNumber(), '3.9', '>')) {
+        if (version_compare($this->appbox->get_version(), '3.9', '>=')) {
             return [];
         }
 
-        $sql = 'SELECT usr_mail, usr_id, last_conn, usr_login FROM '. $table .' WHERE usr_mail IS NOT NULL';
-        $stmt = $app['phraseanet.appbox']->get_connection()->prepare($sql);
-        $stmt->execute();
+        $builder = $this->appbox->get_connection()->createQueryBuilder();
+        /** @var Statement $stmt */
+        $stmt = $builder
+            ->select('u.usr_mail', 'u.usr_id', 'u.last_conn', 'u.usr_login')
+            ->from($this->table, 'u')
+            ->where($builder->expr()->isNotNull('u.usr_mail'))
+            ->execute()
+        ;
         $rs = $stmt->fetchAll(\PDO::FETCH_ASSOC);
         $stmt->closeCursor();
 
@@ -66,4 +85,14 @@ class MailChecker
 
         return $badUsers;
     }
+
+    /**
+     * Whether there is users with same emails
+     *
+     * @return bool
+     */
+    public function hasWrongEmailUsers()
+    {
+        return count($this->getWrongEmailUsers()) > 0;
+    }
 }
diff --git a/lib/classes/Setup/Upgrade.php b/lib/classes/Setup/Upgrade.php
index 6220eb4884..3fb0c6d299 100644
--- a/lib/classes/Setup/Upgrade.php
+++ b/lib/classes/Setup/Upgrade.php
@@ -39,8 +39,8 @@ class Setup_Upgrade
 
         $this->app = $app;
 
-        if (version_compare($this->app['phraseanet.appbox']->get_version(), '3.9', '<')
-                && count(MailChecker::getWrongEmailUsers($app)) > 0) {
+        $checker = new MailChecker($app['phraseanet.appbox']);
+        if ($checker->hasWrongEmailUsers()) {
             throw new \Exception_Setup_FixBadEmailAddresses('Please fix the database before starting');
         }
 
diff --git a/lib/classes/module/console/systemMailCheck.php b/lib/classes/module/console/systemMailCheck.php
index ca93ed0313..17633eb4fd 100644
--- a/lib/classes/module/console/systemMailCheck.php
+++ b/lib/classes/module/console/systemMailCheck.php
@@ -35,15 +35,15 @@ class module_console_systemMailCheck extends Command
     {
         $output->writeln("Processing...");
 
-        $bad_users = [];
-        if (version_compare($this->getService('phraseanet.appbox')->get_version(), '3.9', '<')) {
-            $bad_users = MailChecker::getWrongEmailUsers($this->container);
-        }
+        /** @var appbox $appBox */
+        $appBox = $this->getService('phraseanet.appbox');
+        $checker = new MailChecker($appBox);
+        $bad_users = $checker->getWrongEmailUsers();
 
         foreach ($bad_users as $email => $users) {
             if ($input->getOption('list')) {
-                $this->write_infos($email, $users, $output, $this->getService('phraseanet.appbox'));
-            } elseif ($this->manage_group($email, $users, $output, $this->getService('phraseanet.appbox')) === false) {
+                $this->write_infos($email, $users, $output, $appBox);
+            } elseif ($this->manage_group($email, $users, $output, $appBox) === false) {
                 break;
             }
 
diff --git a/tests/Alchemy/Tests/Phrasea/Setup/Version/MailCheckerTest.php b/tests/Alchemy/Tests/Phrasea/Setup/Version/MailCheckerTest.php
index ac359932b4..ef5a579ed3 100644
--- a/tests/Alchemy/Tests/Phrasea/Setup/Version/MailCheckerTest.php
+++ b/tests/Alchemy/Tests/Phrasea/Setup/Version/MailCheckerTest.php
@@ -8,8 +8,13 @@ class MailCheckerTest extends \PhraseanetTestCase
 {
     public function testMailChecker()
     {
-        $users = MailChecker::getWrongEmailUsers(self::$DI['app'], 'usr_tmp');
+        $checker = new MailChecker(self::$DI['app']['phraseanet.appbox'], 'usr_tmp');
+        $this->assertEmpty($checker->getWrongEmailUsers());
+    }
 
-        $this->assertEquals(0, count($users));
+    public function testItHasNoDuplicateEmailUsers()
+    {
+        $checker = new MailChecker(self::$DI['app']['phraseanet.appbox'], 'usr_tmp');
+        $this->assertFalse($checker->hasWrongEmailUsers());
     }
 }