卸载旧版本的MySQL后，在Windows上全新安装MySQL 5.6.15时，访问被拒绝用户'root'@'localhost'“

Question

So, I've just installed MySQL 5.6.15 on my Windows machine, but for some reason I can't log in using "root" with no password.

C:\web\mysql-5.6.15-win32\bin>mysql.exe -u root
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

However I can login with "ODBC" and no password:

C:\web\mysql-5.6.15-win32\bin>mysql.exe
Welcome blah blah blah
mysql> SELECT USER();
+----------------+
| USER()         |
+----------------+
| ODBC@localhost |
+----------------+
1 row in set (0.00 sec)

Why can't I log in with "root" with no password? I've tried uninstalling MySQL and installing it again, to no avail.

Answer 1

I still don't know why there isn't a "root" account without password by default, but here's how I solved the problem:

1. Stop the MySQL service (mysqld.exe)
2. Start the MySQL service with the following parameter: --skip-grant-tables
3. Log in to MySQL (mysql.exe) as root: mysql.exe -u root (it doesn't require a password, thanks to step 2)
4. Execute the following queries: UPDATE mysql.user SET Password=PASSWORD('') WHERE User='root'; FLUSH PRIVILEGES; UPDATE mysql.user SET Password=PASSWORD('') WHERE User='root'; FLUSH PRIVILEGES;
5. Exit MySQL
6. Stop the MySQL service
7. Start the MySQL service without the --skip-grant-tables parameter

Answer 2

OK, I think I found out what the problem was:

I uninstalled MySQL 5.1.70 by doing:

C:\web\mysql-5.1.70\bin>mysqld.exe --remove

It worked.

Then I installed MySQL 5.6.15 by doing

C:\web\mysql-5.6.15-win32\bin>mysqld.exe --install

It appeared to work. In fact what it did was re-installing the old version.

The solution is to rename or delete the old folder (C:\\web\\mysql-5.1.70) before running mysqld.exe --install

EDIT: Now I understand. C:\\web\\mysql-5.1.70\\bin was in my Path...

Answer 3

I had the same security issue when I had a fresh install of Mysql on windows after uninstalling the old version. I figured out a way that could possiblely resolve the problem:

After you have installed the new version of MySQL, go to MySQL\\MySQL Server 5.5\\bin and launch MySQLInstanceConfig.exe . This will help you to reset your password and config will work well