Why Disk Cleanup Isn't Working: the Real Reasons Your Drive Stays Full
When cleanup 'doesn't work', the tool usually isn't broken — it's cleaning the wrong place. Temp files are a few hundred MB; your missing tens of GB live in chat archives, dev caches and leftovers from uninstalled software.
Check what your cleaner actually covers: most scripts only handle temp/Recycle Bin/browser caches — usually under 1GB combined. If you are missing tens of GB, that is the wrong battlefield
Find the real space hogs: sort user folders by size (chat apps and dev-tool caches under AppData are often 5-20GB each)
Watch for orphaned data: uninstalled apps can leave huge data vaults behind — in one real case, a leftover "mover" folder from an uninstalled utility hid 72GB of archived files
Watch for outdated cleanup scripts: batch files written for Windows 7 clean paths that no longer exist on Windows 10/11 — they run successfully and delete nothing
Fix the root cause: move chat storage to another drive, move dev caches (npm config set cache D:\npm-cache), disable hibernation you never use (powercfg /h off) — after these three, "regular cleanup" mostly becomes unnecessary
Work top-down by folder size: find the biggest folder on each drive root, then drill in. For unfamiliar big folders, check for running processes and the Installed-apps list before touching anything.
Can I delete leftovers from uninstalled software?
Inspect the contents first — data vaults can contain your personal files (chat history, backups) mixed with program leftovers. If unsure, rename the folder and wait a few weeks before deleting.