What is a cache, and when should you clear it?

A shortcut for repeated work

Imagine looking up the same term several times and keeping a note beside you. A cache similarly holds available results for later requests. Applications may cache previews, computed information or downloaded content. The exact contents depend on the cache.

Memory caches and cache files are different

Windows also keeps read file data in memory. A later request can be served from the system file cache. An application’s cache files, however, occupy drive space. A faster second scan therefore does not prove that the app created a persistent cache.

Sources: Microsoft Learn: File Caching

When is clearing useful?

Use the application’s own controls where possible. Deleting everything in AppData is not cache cleanup. Settings, profiles and your own work may live there too.

• A particular cache takes substantial space and you do not currently need its stored content.
• The application’s help recommends clearing it for a specific display or refresh problem.
• You want to remove cached content from a shared device. Review history and account data separately; these are not necessarily the same storage.

What happens afterwards?

Anything still needed has to be loaded or computed again. Think of a large photo list with no existing thumbnails: building it the first time can take work again. That alone does not indicate a new fault.

A useful question is whether you are trying to free space, fix a problem or simply make a number smaller. The first two goals usually provide a better reason for deliberate cleanup.

DiscReveal’s optional cache

The duplicate finder can remember short content fingerprints and file metadata. Unchanged files can skip that preliminary check next time. Confirmed matches are still compared in full. A cache hit alone never triggers cleanup.

The cache is off by default. If enabled, it lives locally in AppData. The app shows its size and lets you clear it. Drive-scan results instead stay in memory only for the session.