Windows Update Takes Up a Lot of Space: How to Free It Afterwards
What the Windows.old folder is and how to free it up safely, with the step almost everyone skips.
You just updated Windows and suddenly have 10-20 GB less free space. It's not a bug — it's a specific folder keeping a backup, and it can be safely freed up after a while.
The culprit: the Windows.old folder
After a major update, Windows keeps a full copy of your previous
installation in a folder called Windows.old — in case
you need to go back. It usually takes up more than 20 GB. After 10
days, Windows deletes it automatically on its own, but you can free
it up manually sooner if you need the space right away.
How to free it up
- Search for "Disk Cleanup" in Windows.
- Select the "C:" drive.
- Click "Clean up system files" — this is the step almost everyone skips, and without it you won't see the Windows.old option in the list.
- Check "Previous Windows installation(s)".
- OK.
Warning: once this folder is deleted, you won't be able to go back to the previous version of Windows if something goes wrong with the new one. It's an irreversible decision — make sure the current update works well before freeing up this space.
Before updating: temporarily compress the drive
If Windows warns you that you don't have enough space BEFORE it can update, you can temporarily compress the system drive: right-click "C:" → Properties → "Compress this drive to save disk space". You can decompress it afterwards the same way.
If you're still short on space
Our guide on how to free up disk space on Windows 11 covers more general options, beyond the update-specific ones.
Tip: if your machine is usually low on disk space (like many budget laptops with 32-64 GB), Windows also offers you the option of temporarily using an external USB drive during the update process, instead of having to free up internal space every time.
Frequently asked questions
Is it safe to delete the Windows.old folder?
Yes, once enough time has passed that you trust the new version works well. Keep in mind that once deleted, you won't be able to go back to the previous version of Windows if a problem appears.
Why don't I see the option to remove Windows.old in Disk Cleanup?
You're missing the 'Clean up system files' button inside Disk Cleanup itself — without that step, this specific option doesn't appear in the list.
Does Windows delete this folder automatically at some point?
Yes, 10 days after the update, Windows removes it on its own. You only need to free it up manually if you need that space before those 10 days pass.