AFAIU, OS X has a collection of built in users, and one of these users is 'mysql' user.
The reason I am making this guess is, the first time I have installed mysql server using the dmg, it installed fine. However, later I have uninstalled it and deleted mysql users. When I wanted to reinstall it later again from dmg, the installation kept failing until I recreated the 'mysql' user and 'mysql' group.
So, is there any way to recover the built in Directory Service data (such as Users, Groups, etc.)?