Windows leaves behind gigabytes of junk when you uninstall apps -- here's how to find it

Uninstalling an app on Windows usually leaves behind files and metadata the standard uninstaller doesn’t fully track. As the article explains, Windows removes only what it has on a fixed list from the original installation, while anything created later—such as user caches, configuration files, and temporary data in folders like AppData and Temp—often remains. Windows also avoids deleting files marked as permanent and uses reference counting for shared files, which can preserve unused remnants. The result can include “gaps” in the registry and NTFS records in the Master File Table, slowing lookups and, in worse cases, contributing to Windows Update failures. Third-party uninstallers are suggested as a cleaner alternative.