How to free up disk space on Windows 11 without deleting anything you need

A full Windows drive is rarely full of your files. It is usually full of files Windows made for its own purposes and then stopped needing.

This guide was checked on Windows 11 24H2 (build 26100). The paths are the same on 23H2; on Windows 10 the Settings layout differs but the underlying tools are identical.

Work through these in order. The first two are safe on any machine. The third and fourth have real trade-offs, which are stated.

1. Cleanup recommendations

Go to Settings > System > Storage > Cleanup recommendations.

This is the single most productive screen in Windows for this problem, because it groups the four big categories together and tells you the size of each before you commit:

• Temporary files - update caches, delivery optimisation files, error reports, thumbnails.
• Large or unused files - sorted by size, so a forgotten 8 GB ISO surfaces immediately.
• Files synced to the cloud - already in OneDrive, still taking local space.
• Unused apps - sorted by last-opened date.

Tick what you want and select Clean up. Nothing here removes a file that only exists locally without telling you first.

2. Turn on Storage Sense so this does not recur

Same Storage page, Storage Sense at the top. Switch it on and open it.

Set Run Storage Sense to Every week. Leave Delete files in my Downloads folder on Never unless you genuinely treat Downloads as disposable - this is the one setting here that can remove something you wanted.

This is the difference between cleaning up once and never thinking about it again.

3. Remove Windows.old, if it is there

After a feature update, Windows keeps the entire previous installation in C:\Windows.old so you can roll back. It is typically 15-25 GB.

It appears under Cleanup recommendations as Previous Windows installation(s). Windows deletes it on its own roughly ten days after the upgrade.

The trade-off: removing it ends your ability to roll back to the previous version. If the machine has been stable since the update, that is a fair trade. If you updated yesterday and something feels wrong, wait.

4. Disable hibernation, if you never use it

hiberfil.sys holds the contents of RAM when the machine hibernates. It is sized in proportion to installed RAM - on a 16 GB machine, expect several gigabytes.

Open Terminal as administrator and run:

powercfg /hibernate off

The file disappears immediately.

The trade-off, and it is a real one: this also disables Fast Startup, which uses the same file. Cold boots will be slightly slower, and the Hibernate option disappears from the power menu. On a desktop that is always plugged in, that is usually fine. On a laptop you regularly close mid-work, it is not - hibernate is what preserves your session when the battery runs out.

To reverse it:

powercfg /hibernate on

What not to bother with

• Registry cleaners. They do not free meaningful space and can break a working system.
• Deleting files in C:\Windows\WinSxS manually. It looks enormous, but hard links mean it is much smaller on disk than reported, and manual deletion breaks servicing. Use Dism /Online /Cleanup-Image /StartComponentCleanup if you must.
• Emptying the page file. Windows manages it, and shrinking it trades disk space for stability under memory pressure.

If it is still full

At this point the space is genuinely yours. Sort by size in Cleanup recommendations > Large or unused files and decide what to keep. Games and video are almost always the answer.