Mail attachments and downloaded update data can use substantial storage. They should be reviewed differently from ordinary caches because losing offline access or interrupting an update can be inconvenient.
Before cleaning Mail attachments
Confirm that important attachments still exist in the original message, mail server, or another backup. If an account was removed, a message exists only locally, or a file is needed offline, preserve its cached attachment.
Quit Mail before removal so it is not actively reading or downloading the same files.
Scan attachment cache
- Open Cleanup.
- Choose Mail Attachments Cache.
- Grant the requested folder access if you want the tool to inspect the Mail data location.
- Start the scan.
- Review account, mailbox, date, size, and path information provided by the result.
- Deselect anything you need offline.
- Confirm removal.
Afterward, Mail may download an attachment again when you open its message.
Before cleaning update cache
Do not clean update data while:
- System Settings shows a macOS update downloading, preparing, or installing.
- The Mac is waiting to restart for an update.
- An application installer is running.
- You are diagnosing a failed update and may need its logs or package.
Scan supported update files
- Open Cleanup.
- Choose System Update Cache.
- Start the scan.
- Review the identified location and file dates.
- Confirm that no related update is active.
- Select and remove only the supported files you no longer need.
Some protected update locations can require folder access, Full Disk Access, or action-specific authorization.
If results are empty
An empty result can mean there is nothing supported to remove, macOS already cleaned the cache, or diCleaner cannot access the location. Review permissions and run a new scan, but do not assume an active update failed solely because no cache is shown.
After cleaning
Open Mail or Software Update normally. A recreated cache or repeated download is expected when the underlying content is still needed.