A master reset is a full restore of a hanheld computer (or PDA) to its factory settings. It entails deleting all information stored in the handheld. This is essentially the same as reformatting a hard drive. A master reset may become necessary from time to time on a PDA which has too many unreliable programs on it, thus restoring integrity to the system. It should be used with caution, as it destroys all data stored in the unit.