diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
index 899f927743..3b81f11c4d 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
@@ -52,4 +52,12 @@ class MySqlExpressionBuilder extends ExpressionBuilder {
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->comparison($x, ' COLLATE ' . $this->charset . '_general_ci LIKE', $y);
 	}
+
+	public function eq($x, $y, $type = null) {
+		return 'BINARY ' . parent::eq($x, $y, $type);
+	}
+
+	public function neq($x, $y, $type = null) {
+		return 'BINARY ' . parent::neq($x, $y, $type);
+	}
 }
diff --git a/lib/private/User/Manager.php b/lib/private/User/Manager.php
index 303050a771..e55d439519 100644
--- a/lib/private/User/Manager.php
+++ b/lib/private/User/Manager.php
@@ -188,7 +188,7 @@ class Manager extends PublicEmitter implements IUserManager {
 	 */
 	public function userExists($uid) {
 		$user = $this->get($uid);
-		return ($user !== null);
+		return $user !== null && $user->getUID() === $uid;
 	}
 
 	/**