I’m sure that many of you keep all sorts of important research data locked away in a local MySQL installation. If you had installed MySQL on Tiger using the official MySQL installation package and upgraded your system to Leopard, you’ll find that your MySQL Preferences Pane can no longer be used to start and stop MySQL. If you used the “Archive and Install Security” upgrade mechanism you can follow these directions to repair your MySQL installation. If you did a straight upgrade or migrated your MySQL via some other means, you might give these instructions a try.