Check Software Update
Do not remove cache while an update is downloading, preparing, installing, or waiting for restart. Finish or resolve the update first.
Restart
Restart the Mac after a completed or failed update, then run a new scan.
Review access
Supported locations can require Home-folder access, a selected folder, Full Disk Access, or action-specific authorization.
Respect protected files
macOS can retain files needed for recovery or continued installation. Do not disable System Integrity Protection or manually change system ownership to force deletion.
Result changed
macOS may remove or replace update files between scan and confirmation. A stale result can fail because the original path no longer exists.
If Software Update itself is broken, follow Apple’s update troubleshooting rather than treating cache removal as the only repair.