This beautiful app will show you all the forgotten files that are slowing down your Mac

Where previously workers had great stacks of paper and overflowing filing cabinets surrounding them, many offices are now going completely paper-free.

But replacing this clutter is near-infinite quantities of digital junk: Thousands of virtual folders containing every file you ever forgot you downloaded, quietly taking up space.

Three years-worth of old expense reports? Obsolete induction guides for offices you no longer work in? That hour-long video of the disastrous company all-hands meeting last year? It's all in your laptop somewhere, almost impossible to find and delete.

Luckily, there are apps out there that are a godsend for helping you map your hard drive so you can figure out what's taking up so much space. My favourite for Macs running OS X is called GrandPerspective, and it's free to download and use.

Here's how it works.