If your C: drive is nearly full, the fix usually isn't "delete your files" — Windows accumulates a surprising amount of reclaimable junk on its own. Work through these in order before you touch anything personal.
Step 1: Run Storage Sense
Settings → System → Storage → turn on Storage Sense and click Run Storage Sense now. This clears temporary files, empties the Recycle Bin on a schedule, and cleans up old Windows Update files automatically — it's the single easiest win and touches nothing you'd miss.
Step 2: Check What's Actually Using the Space
Settings → System → Storage shows a breakdown by category (Apps, Temporary files, System, Other).
- "Temporary files" larger than a few GB — safe to clear from this same screen; this is cache and installer leftovers, not your documents.
- "System & reserved" unusually large — often old driver packages or a bloated hibernation file; the built-in Disk Cleanup tool (search "Disk Cleanup," run as administrator, check "Clean up system files") targets this specifically.
- A specific app taking way more space than expected — click into it; some apps (browsers, chat clients) cache gigabytes of data that's safe to clear from within the app's own settings.
Step 3: Uninstall What You Don't Use
Settings → Apps → sort by size, not name. It's common to find a large app installed once and forgotten. Removing unused apps is safer and often frees more space than deleting personal files.
Quick Reference
| Symptom | Likely cause | Fix |
|---|---|---|
| Drive full, no idea why | Accumulated temp/system files | Storage Sense + Disk Cleanup |
| One app using unexpected space | App-level cache | Clear cache from within the app |
| Installed apps you forgot about | Unused software | Uninstall, sorted by size |