Free Up Disk Space on Windows 11 ("Low Disk Space")

Category: Windows 11 · Audience: Customers & Technicians · Est. time: 10–20 min

Summary

A nearly full system drive (C:) makes Windows slow, blocks updates, and triggers "Low disk space" warnings. These steps reclaim space safely without deleting personal files.

Symptoms

• "Low disk space" notification
• Red bar under This PC → C: drive
• Updates failing for lack of space

Solution

1. See what's using space. Settings → System → Storage. It breaks down usage by category (Temporary files, Apps, Documents, etc.).
2. Clear temporary files. Settings → System → Storage → Temporary files → tick items (Windows Update cleanup, Delivery Optimisation files, Recycle Bin, Temp) → Remove files. This is safe and often frees several GB.
3. Turn on Storage Sense. Settings → System → Storage → Storage Sense → On to automatically clean temp files and empty the Recycle Bin on a schedule.
4. Empty the Recycle Bin. Right‑click the Recycle Bin → Empty.
5. Uninstall unused apps. Settings → Apps → Installed apps → sort by Size and remove large apps/games you don't use.
6. Move files to OneDrive / another drive. Use OneDrive Files On‑Demand (files stay in the cloud until opened) or move large folders (Videos, ISOs) to an external/second drive.
7. Remove the old Windows install (Technician). After a feature update, Windows.old can be 20+ GB. Remove via Storage → Temporary files → Previous Windows installation(s). (This removes the ability to roll back the update.)

If that doesn't work

• Use a tool like WizTree (technician) to find hidden large files/folders quickly.
• Check for oversized Outlook .ost/.pst or backup files hiding in the user profile.
• If C: is simply too small, escalate to BBN Support to discuss a larger SSD.

Prevention

• Enable Storage Sense; keep at least 15% of C: free.