macos configure mysql access denied for user 'root'@'localhost'

You can do the following on Mac (El Capitan)

Open a Terminal window, use the command below to stop mysql if it's already running.

sudo /usr/local/mysql/support-files/mysql.server stop

You can also check System Preferences > MySQL to see if it is running

Start MySQL with this command:

sudo /usr/local/mysql/bin/mysqld_safe --skip-grant-tables

Open a new terminal window/tab:

sudo /usr/local/mysql/bin/mysql -u root

This should open "mysql" prompt. Execute the following command:

$mysql> UPDATE user SET authentication_string=PASSWORD("my_password") WHERE User='root';

Troubleshooting tips:

A) The command for MySql versions before 5.7 was:

$mysql> UPDATE user SET Password=PASSWORD('my_password') where USER='root';

B) If you see ERROR 1046 (3D000): No database selected, then run this command first:

use mysql;

C) If you see unknown "Password" field error, then run this command:

UPDATE USER SET AUTHENTICATION_STRING=password('NewPassword') WHERE user='root';
 $mysql> FLUSH PRIVILEGES;
 $mysql> EXIT

Stop MySql server

sudo /usr/local/mysql/support-files/mysql.server stop

Restart MySQL, either through System Preferences > MySql or using a command.