Re: MySQL 9.0 (MacOS) failed to initialize database after installation

[Daniel Fischer]

The _mysql user is not created by our installer. It's a system user that is present on macOS by default. Therefore our installer will not re-create it if it's removed or otherwise modified.

That being said, I could not reproduce this simply by deleting the user in Directory Utility. The entry remained in /etc/passwd and continued to work (you're also still seeing _mysql as the file owner, indicating that this is also the case on your system. If the user was completely deleted, ls would show the numeric user ID and not the name).

Does initializing the data directory via the preference pane also fail?

--
Daniel Fischer, MySQL Release Engineering
Oracle Corporation, http://oss.oracle.com/