I have just installed MySQL and MySQL Workbench.
After installing both, I can see the "MySQL" icon in System Preferences. But if I try to start MySQL Server it asks me the password, but then nothing happens.
So I tried to start MySQL Server from the terminal with the following command:
sudo /usr/local/mysql/support-files/mysql.server start
.. ERROR! The server quit without updating PID file (/usr/local/mysql/data/MBP.local.pid).
Check if a mysql process already exists or not
ps -ef | grep mysql
If yes, Kill the process
kill -9 PID or
killall -9 mysql mysqld
sudo mysql.server start