环境：CentOS 6.5 64bit

创建用户：

mysql> create user 'stalker'@'localhost' identified by '1';

错误ERROR 1396 (HY000): Operation CREATE USER failed for 'stalker'@'localhost'

刷新权限

mysql> flush privileges;

之后再创建用户，还是报错ERROR 1396 (HY000): Operation CREATE USER failed for 'stalker'@'localhost'

尝试删除一次：

mysql> drop user 'stalker'@'localhost' ;

mysql> flush privileges;

mysql> create user 'stalker'@'localhost' identified by '1';

成功。