How-to

C drive full for no reason on Windows 11? Find what is taking the space

A full C drive is rarely mystery files. It is usually Windows Update leftovers, restore points, a hibernation file, and developer and AI folders that Storage settings does not name. Here is how to find each one.

1. Start with Storage settings

Open Settings > System > Storage. Click Temporary files and tick Windows Update Cleanup, Delivery Optimization Files, thumbnails and the Recycle Bin. Leave Downloads unticked unless you have checked it. Turn on Storage Sense to repeat this automatically.

2. Run Disk Cleanup for system files

Press Win+R, type cleanmgr, choose C:, then click Clean up system files. The extra items here, such as Windows Update Cleanup and Previous Windows installation(s), are often the biggest wins. Removing the previous installation means you can no longer roll back.

3. Check the hidden hogs

# hibernation file (admin): size is a large share of your RAM; this also turns off Fast Startup
powercfg /hibernate off

# System Restore storage
vssadmin list shadowstorage

# component store: safe cleanup
DISM /Online /Cleanup-Image /AnalyzeComponentStore
DISM /Online /Cleanup-Image /StartComponentCleanup

Limit restore points under System Properties > System Protection > Configure. Leave pagefile.sys alone.

4. Check the developer and AI folders

This is where "no reason" usually lives. Look in:

C:\Users\<you>\.ollama\models: Ollama models.
C:\Users\<you>\.cache\huggingface\hub: Hugging Face models and datasets.
%LOCALAPPDATA%\Docker\wsl\data\ext4.vhdx: Docker's disk, which never shrinks on its own.
C:\Users\<you>\.claude\projects and C:\Users\<you>\.codex\sessions: coding-agent history.
%LOCALAPPDATA%\Temp: temporary files.

Use ollama rm, huggingface-cli delete-cache and docker system prune rather than deleting inside those folders. For a visual map of everything, a disk-usage viewer such as WinDirStat shows the biggest folders at once.

What is safe and what is not

Safe: temporary files, update and delivery caches, the Recycle Bin, model files you can download again, and Docker's unused images. Not safe: hand-deleting anything in C:\Windows, WinSxS or System Volume Information, or deleting ext4.vhdx, which removes every Docker image and volume.

Or let Prune do it

Prune scans the developer and AI side of your C drive and lists Ollama, Hugging Face, Docker, agent history and caches by name. Your own files go to the Recycle Bin, never straight to oblivion. The free scan shows every file before you pay. Pro is $15 a year or $29 once ($19 until 20 December 2026).

FAQ

Why is my C drive full for no reason on Windows 11?

The usual causes are Windows Update leftovers, System Restore points, the hibernation file, Docker or WSL disk images, and AI model folders in your user profile. Storage settings often shows only part of it.

Is it safe to run Disk Cleanup on system files?

Yes. Windows Update Cleanup, Delivery Optimization files and temporary files are designed to be removed. Only tick Previous Windows installations if you will never roll back.

Can I delete the WinSxS folder?

No. Delete nothing in WinSxS by hand. Use DISM /Online /Cleanup-Image /StartComponentCleanup, which removes only what Windows allows.

Can Prune clear space on my C drive?

Prune covers the developer and AI part: Ollama and Hugging Face models, Docker, agent history, caches and idle project dependencies. Files go to the Recycle Bin after you review them.