MySQL server startup error ‘The server quit without updating PID file’

Try to find your log file with suffix “.err”. There should be more information. It might be in:

/usr/local/var/mysql/your_computer_name.local.err

It’s probably a problem with permissions

Check if any MySQL instance is running
```
ps -ef | grep mysql
```
If yes, you should stop it, or kill the process:
```
kill -9 PID
```
where PID is the number displayed next to the username on the output of the previous command
Check ownership of /usr/local/var/mysql/
```
ls -laF /usr/local/var/mysql/
```
If it is owner by root, you should change it to mysql or your_user
```
sudo chown -R mysql /usr/local/var/mysql/
```

Follow the instructions from brew install mysql.

Set up databases to run as your user account with:

For MySQL 5.x:

unset TMPDIR
mysql_install_db --verbose --user=`whoami` --basedir="$(brew --prefix mysql)" --datadir=/usr/local/var/mysql --tmpdir=/tmp

To set up base tables in another folder, or use a different user to run mysqld, view the help for mysqld_install_db:

mysql_install_db --help

And view the MySQL documentation:

For MySQL 8.x:

unset TMPDIR
mysqld --initialize-insecure --log-error-verbosity --user=`whoami` --basedir="$(brew --prefix mysql)" --datadir=/usr/local/var/mysql --tmpdir=/tmp

Make sure the data directory /usr/local/var/mysql above is empty. Back it up if necessary.

To run as, for instance, user “mysql”, you may need to sudo:

sudo mysql_install_db ...options...

Start mysqld manually with:

mysql.server start

Note: if this fails, you probably forgot to run the first two steps up above