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Mrchtopherrr's avatar
Mrchtopherrr
Iron Contributor
Aug 13, 2025

How to free up space in c drive in windows 10 or windows 11?

Hi all, I have two budget PCs at my home and both of them only has 128 SSD. Now, the c drive is almost full and the devices are running very slow. I already deleted the large files from the computer...
SigSoldier's avatar
SigSoldier
Iron Contributor
Aug 13, 2025

A fresh installation of Windows 10 typically requires around 20–25 GB of space. However, over time, with updates, temporary files, and installed programs, the space usage can grow significantly (often 40 GB or more). Hence, 128GB SSD is a bit in short.

To free up space in c drive on windows 10, you can simply compact the os. It is a feature in Windows 10/11 that reduces the size of system files by compressing them (similar to how files are compressed in a ZIP folder). This can free up several gigabytes (GB) of space on your C: drive, but it may slightly impact performance (though usually not noticeable on modern PCs with SSDs).

First, run the following command to enable compression. It will free up space in c drive by compressing the files.

compact /compactos:always

This will compress system files and show how much space was saved. Example output:

XXXX files within XXXX directories were compressed.
Saved: XX.XX GB

Pros:
✅ Frees up significant space    

✅ No data loss    

✅ Reversible at any time  

Cons:

⚠️ Slightly slower file access (mostly on HDDs)

⚠️ Minor increase in CPU usage

⚠️ Not recommended for high-performance systems

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