All guides · 6 min read

Free up disk space on Windows – in the right order

Where the space on your drive actually goes, which steps give you the most back, and what to keep your hands off.

Windows tends to report “low disk space” at the worst possible moment. The first reflex – deleting some holiday photos – rarely helps, because the space is tied up elsewhere. So it pays to look first and act second.

Look where the space went

Windows ships an overview that hardly anyone knows: Settings → System → Storage. It shows how much goes to apps, temporary files, documents and pictures. That single page saves you hours of guessing.

For individual folders, Explorer is enough: right-click a folder → Properties shows the total size including subfolders. A few clicks tell you which branch is genuinely heavy.

The order that gives you the most back

1. Empty the recycle bin. It sounds trivial and is often a double-digit number of gigabytes – deleted files still sit on the disk.
2. Go through the downloads folder. Installers, ISO files and ZIP archives you needed exactly once.
3. Run Disk Cleanup, including the “Clean up system files” button.
4. Only then go for your own files – duplicates, old videos, backup copies.

Disk Cleanup is the underrated item. The “Clean up system files” button matters: only afterwards does the entry “Previous Windows installations” appear. After a large Windows update that can be up to 20 GB, which would vanish by itself after a month anyway.

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Duplicates are the second big item

In anything that has grown over years, a surprising share sits on the disk twice: the same photos from three phone imports, the same folder once more as a “backup”, the same PDF invoice downloaded twice.

This is the only space you can win back without giving anything up – you lose nothing when one of two identical files goes. The only thing that matters is that “identical” really means identical: the content is compared, not the name.

What does not help

• Registry cleaners – the registry takes up a few megabytes, there is nothing to win there
• “PC accelerators” promising all-round care – at best they delete the same things Disk Cleanup does
• Shrinking the page file – saves little and can make the system slower
• Deleting all system restore points – a one-off gain that takes away your safety line

One system file is worth an exception: if you never use hibernation, you can switch off “hiberfil.sys”. It is sized after a substantial part of your RAM – with 16 GB installed, often several gigabytes.

With Zortio

Zortio is built for the fourth step. The duplicate search compares byte for byte and shows you in the preview how much space would actually be freed, before anything moves.

Nothing gets deleted. Duplicates move into a folder called “Duplicates – can go” that you review and delete yourself. That detour is what stops a program from clearing away the only copy of a family photo.