ShrinkCheck Privacy Policy

Last updated: November 14, 2026

atelier-flare ("we", "us") respects your privacy when you use the macOS app ShrinkCheck (named CmpfsCheck through version 0.9.x; the "App") and handles information according to the following policy. The App does not require you to create an account or enter a license key.

This is an English translation provided for convenience. If there is any discrepancy between this translation and the Japanese version, the Japanese version prevails.

1. Information the App Stores

The App stores the following information on your Mac.

Paths and security-scoped bookmarks of the files and folders you register
Summary values for each registered item (number of files, numbers of compressed and uncompressed files, total sizes, and the time they were last checked)
The history of compression and decompression runs (path, size before and after, duration, and result)
Identifying information for files recorded as "does not shrink" (to avoid retrying them)
The combinations of OS version and App version that have passed the self-check
The most recently fetched stop notices (see Section 3)
App settings (monthly reminder on/off, log retention policy, stop-notice check on/off, and so on)

This information is stored only on your Mac and is not sent to any server, including ours.

2. Handling of Your Files

The App applies or removes APFS transparent compression (decmpfs) only for the files and folders you explicitly register. The contents of those files are processed only on your device and are never sent outside it, including to our servers.

For the self-check (which confirms that compression and decompression work correctly in your environment), the App creates test files in its own temporary folder and deletes them when the check finishes. Your files are never used for the self-check, and its result is not sent anywhere.

3. Communication with External Services

Versions of the App up to 0.9.x do not communicate with any external server. Version 1.0.0 and later performs only the following one kind of communication.

Checking stop notices and the latest version: The App fetches a public file (status.json) from our server (www.atelier-flare.com) over HTTPS. The file lists the versions for which compression should be suspended for safety reasons, and the latest version number. The App fetches it at launch, about every 24 hours while running, and before an automatic recompression started from the command line.

This communication only receives a public file. The App sends no information.

The request contains no information that identifies your device or you, and does not contain the App version, the OS version, or any information about your files. The User-Agent is a fixed string shared by all users, and cookies are not used
Whether your version is subject to a suspension, and whether a newer version exists, is determined on your Mac from the fetched list
As with any network communication, your IP address reaches the servers of Cloudflare, which we use for delivery, and Cloudflare temporarily keeps the logs needed to operate its infrastructure. We do not record or count fetches of this file, and we do not use them to identify or analyze individuals

You can turn this check off in the App's settings. If you turn it off, or if network access is blocked, the App decides using only the stop notices bundled with it and those it last fetched. In that case you will not receive suspensions for problems discovered after release, or notices of newer versions. Compression, decompression, and all other features work with or without network access.

The App performs no communication for usage analytics, behavioral tracking, or crash reporting.

4. Apple Intelligence

The App may use Apple Intelligence (an on-device language model) to help you judge what a file is for and whether it is safe to delete. Processing is completed on your Mac, and neither file metadata nor prompts are sent to external servers, including Apple's and ours.

5. Cloud-Synced Folders

If you process files inside a cloud-synced folder such as iCloud Drive, Dropbox, or OneDrive, the cloud service may upload the compressed result again, depending on how that service works. Communication with those services is governed by their own privacy policies. The App shows a warning about this risk when you register such a folder.

6. Tracking and Advertising

The App uses no mechanism that tracks your behavior, no analytics tags, and no crash report collection. It displays no advertising.

7. Deleting Your Data

All information the App stores is on your Mac. Deleting the app itself leaves your registered items, history, and settings in ~/Library/Application Support/CmpfsCheck/ (the folder keeps the old name after the rename) and related locations. To remove everything, delete that folder as well. Because none of your information is stored on our servers, you do not need to ask us to delete anything.

8. Contact

For questions about this policy, please contact us.

Contact: [email protected]

9. Changes

We may revise this policy as needed without prior notice. A revised policy takes effect when it is posted on this page.