How to free up disk space on Windows 10 and 11

The fastest way to free space is to find the few folders that hold most of it, then clean those. Deleting small files at random frees almost nothing and is where most accidents happen.

1. Measure before you delete

Open Settings, System, Storage. Windows lists categories (Apps, Temporary files, Documents) and how much each uses. It is a good first look, but it groups things by type, not by folder, so it cannot tell you that one 60 GB folder under AppData is the whole problem.

A disk space analyzer scans the drive and draws every folder and file to scale. The biggest rectangle is where to start. Bytopsy's folder view and treemap do this, and so do WinDirStat, WizTree and TreeSize. See what is taking up space on your C: drive for how to read the result.

2. Use what Windows already gives you

• Storage Sense and Temporary files. In Settings, System, Storage, open Temporary files. Previous Windows installations, Delivery Optimization files and update leftovers are listed with sizes. Read the list: Downloads is on it, and it is your own files.
• Disk Cleanup. Run cleanmgr, then Clean up system files for Windows Update cleanup and old setup files.
• Uninstall what you do not use. Settings, Apps, Installed apps, sorted by size. Game libraries and creative suites are usually the biggest.

3. The usual big offenders

• Downloads and old installers. Sort by size and by age. Setup files you already ran are safe to remove.
• Videos and disk images. A few .iso, .mkv or screen recordings are often the largest items on a drive. Search for them with a size filter such as >1G.
• Developer caches. npm, pip, Gradle, NuGet, Cargo, Maven and Docker caches grow quietly and are rebuilt on demand. Old node_modules folders in projects you stopped touching are the classic one.
• AI models. Hugging Face and Ollama downloads run to tens of gigabytes each and are easy to fetch again.
• WSL and Docker disks. Their virtual disks never shrink by themselves. Here is how to compact them.
• Duplicates and similar photos. Duplicate finders compare size, then a hash. Keep one copy of each, and never auto-delete in your Documents or Pictures folders without looking.

4. Space Windows keeps for itself

These are real, but each has a trade-off, so change them knowingly.

• Hibernation file. hiberfil.sys is sized from your RAM. If you never hibernate, powercfg /hibernate off removes it, at the cost of Fast Startup. powercfg /h /type reduced keeps Fast Startup with a smaller file.
• System Restore. Restore points live in System Volume Information. You can cap their share of the drive with vssadmin resize shadowstorage /for=C: /on=C: /maxsize=5% instead of switching protection off.
• The component store (WinSxS). Never delete files in it by hand. Ask Windows: DISM /Online /Cleanup-Image /AnalyzeComponentStore, and if it recommends it, DISM /Online /Cleanup-Image /StartComponentCleanup. File Explorer overstates its size because of hard links.
• pagefile.sys. Leave it alone. Windows manages it, and removing it causes crashes under memory pressure.

5. What not to delete

Do not delete anything in C:\Windows (except what Disk Cleanup offers), System Volume Information, C:\Windows\Installer, or the roots of Program Files and AppData. Be careful with browser profiles, SSH keys, wallets, mail archives and game saves: they look like clutter and are not.

Send deletes to the Recycle Bin first, and empty it after you have checked that nothing is missing. Registry cleaners are not on this list for a reason: they free nothing and risk a lot.

Doing it with Bytopsy

Bytopsy follows this order on purpose. You scan, see the treemap, and clean from the same window. Every cleanup item is measured first and checked against protection rules (Blocked, Important and Caution), deletes go to the Recycle Bin by default, and a journal lets you restore them. It also covers the Windows items above (hibernation, restore points, the component store) using Windows' own tools, and it is free and open source.