First download Disk Drill, Mac file system recovery software. Installing is as easy as dragging it to your Applications folder and authorizing Disk Drill to scan your drives. You'll need to enter your administrator password for this. Optionally, drag the Disk Drill application to the Dock for easy access.
Disk Drill has some unique protection possibilities to make sure no data will be lost. Those are Recovery Vault and Guaranteed Recovery features. Recovery Vault draws a "map" for Disk Drill to find lost files, while Guaranteed Recovery is always keeping track on files and in case they are moved to Trash it saves their invisible copies to ensure successful recovery whenever needed.
Disk Drill offers Deep Scan that is exceptionally effective for the situations with hardly any file structure left. Doesn't matter if it is HFS recovery on Mac OS X, or NTFS, or FAT32, Disk Drill will apply its great knowledge of file signatures to find the correct ones and restore all your files including XLS, DOC, AVI, MP4, JPG, and others.