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What's Taking Up Space on Your Windows PC? How to Actually Find Out

2026 · 6 min read

"Local Disk (C:) is almost full" is one of the more frustrating Windows messages, mostly because it doesn't tell you why. File Explorer alone makes this surprisingly hard to figure out.

Why File Explorer doesn't really help

Right-clicking a folder and choosing Properties shows a total size, but calculating it can take a long time on a large folder, and you have to do it one folder at a time, guessing where to look next. There's no built-in view that just shows you the biggest things on a drive, sorted, in one pass.

Start with Settings, for a rough picture

Settings > System > Storage gives a breakdown by category (Apps, Documents, Temporary files, and so on). It's a reasonable starting point, but the categories are broad. "Apps" doesn't tell you which app, and "Other" is often the largest category and the least informative.

The usual suspects worth checking directly

• Downloads folder - installers and videos accumulate here for years without anyone noticing.
• Hibernation file (hiberfil.sys) - reserves space equal to a portion of your RAM, invisible unless you know to look for it.
• Virtual machine disk files - a single VM image can be tens of gigabytes, and they're easy to forget about once a project is done.
• Game installs - modern games routinely exceed 50-100 GB each; a handful of uninstalled-in-spirit-but-not-in-practice games add up fast.
• Browser caches and profile data - spread across Chrome, Edge, and Firefox if you use more than one.
• node_modules and build folders - if you do any development work, old project folders can hide gigabytes of dependencies you'll never reinstall from.

OneDrive files can be misleading

If you use OneDrive with Files On-Demand, some files shown in Explorer are just placeholders, not stored locally, while others are fully downloaded. A folder that looks huge in OneDrive's web view might barely touch your local disk, and vice versa, which can throw off manual estimates.

A dedicated scan is the fastest path

The most direct way to answer "what's using my space" is a tool built specifically to walk the whole drive once and rank folders and files by size. That's the entire job PurgeCore does: point it at a drive, and it shows the largest folders and files, a breakdown by category, and the oldest files you've likely forgotten about, without uploading anything about your files anywhere.

Once you know where the space is

Finding the source is the useful part, deciding what to do about it is usually straightforward once you can see it: uninstall the game, delete the old VM image, clear the browser cache, or just leave it if it turns out to be something you actually need.