When your hard drive fills up with too much data, it's hard if not impossible to find the large data quickly and easily. Enter TreeSizeFree. TreeSizeFree is a free utility that comes in installable or portable flavors. While there are other open source projects that produce these GUI, TreeSizeFree is by far the best working and best looking. Scan results allow you to drill down and open the folders directly to the largest offending files for removal.