Troubleshooting & messages · Free space and clean-up messages
Why does a clean-up say some items were "left alone"?
Short answer: Any item Storage Studio couldn't confirm as safe — real cache, not in use, not recently used — is left alone. An unanswered safety check counts as no; later runs often clear them.
Before clearing anything, Storage Studio confirms it's what it looks like (a real cache or temporary folder), that nothing is using it, and how recently it was used. If any of those checks can't be completed, it leaves the item alone — an unanswered safety question counts as a "no".
Skipped items are usually cleared on a later run, when nothing is holding them.