Free Space is a full-featured free space monitor and 1-click ejector. On OS X 10.7 and forward, the local snapshot is switched on by default by Apple. That means that some space would have been taken and hidden as a local backup inside OS X. Finder always displays the available space disregarding the local snapshots, but FreeSpace displays the true available space with regard to the presence of the snapshots.
Mall Creeps
