AppleJack is a user friendly troubleshooting assistant for Mac OS X. With AppleJack you can troubleshoot a computer even if you can`t load the GUI, or don`t have a startup CD handy. AppleJack runs in Single User Mode and is menu-based for ease of use Features disk repair in single user modepermissions repair in single user modecache cleaning in single user modepreference file check in single user