Go to CleverFiles.com and click on the green Download button to download the absolutely free Disk Drill Basic. The Basic version is all you need to create a free disk map and analyze the disk usage on your Mac. Once you have downloaded the install file, double-click on it and follow the installation instructions.
Disk Drill can pretty quickly check your Mac hard drive space and map it out for you to show what's "eating" your disk space. Move duplicates and unneeded files to Trash and don't you worry — Disk Drill makes sure you don't trash system files. Benefit from flexible filters and three display modes. Network drives are also supported.
Our disk space analyzer for Mac OS X offers Deep Scan that combs through the raw data from any storage device. It won't matter whether the drive is FAT, NTFS, or else. Disk Drill goes through the available fragments of your files getting them together as a puzzle with all of its knowledge of file signatures.