If you've recently upgraded to macOS Sequoia 15.0 and are experiencing issues with MySQL not running, you're not alone. This guide will walk you through the steps to resolve this issue, especially if you're upgrading to MySQL version 9 or above.

You might encounter error messages like this:

ERROR 2002 (HY000): Can't connect to local server through socket '/tmp/mysql.sock' (2)

The root cause lies in the significant architectural changes introduced in MySQL 9.0. Upgrading directly from older MySQL versions (pre-8.4) to 9.0 or later often bypasses crucial compatibility steps, leading to startup failures.

Here's the solution, broken down into actionable steps:

Stop MySQL 9.x

Stop the existing MySQL service: If you have a currently running MySQL service (even if it's malfunctioning), stop it first:

brew services stop mysql

Install MySQL 8.4

We need to install MySQL 8.4 on our machine.

brew install mysql@8.4

Start and Stop MySQL 8.4

Briefly start and then stop the MySQL 8.4 service. This crucial step performs necessary database migrations and prepares the system for the final upgrade.

brew services start mysql@8.4

brew services stop mysql@8.4

Start MySQL 9.x

Now, start your desired MySQL version (9.0 or later). It should now launch correctly:

brew services start mysql

Remove MySQL 8.4

Finally, you can safely remove MySQL 8.4 from your system.

brew remove mysql@8.4

By following these steps, you can resolve the MySQL startup problem on macOS Sequoia 15.0.