MySQL does not start when upgrading OSX to Yosemite or El Capitan

Open a terminal:

1. Check MySQL system pref panel, if it says something along the line “Warning, /usr/local/mysql/data is not owned by ‘mysql’ or ‘_mysql’

2. If yes, go to the mysql folder cd /usr/local/mysql

3. do a sudo chown -R _mysql data/

4. This will change ownership of the /usr/local/mysql/data and all of its content to own by user ‘_mysql’

5. Check MySQL system pref panel, it should be saying it’s running now, auto-magically. If not start again.

6. Another way to confirm is to do a

   netstat -na | grep 3306

It should say:

tcp46      0      0  *.3306                 *.*                    LISTEN

To see the process owner and process id of the mysqld:

ps aux | grep mysql