Privacy policy

Sundial for macOS · Effective September 8, 2026

Sundial measures folder sizes on your Mac. It has no account system, no analytics, no advertising, and no tracking. It contains no networking code and sends nothing anywhere.

What Sundial reads

You choose the folders Sundial can scan through the macOS folder picker. Inside a chosen folder, Sundial reads these attributes for every item: the name, the device identifier, the object type, the file identifier, the hard-link count, and the allocated size on disk. It reads the total capacity, the available capacity, the mount point, and the identifier of the volume the folder is on. It reads the macOS filesystem event journal for the chosen folder to find which subfolders changed since the last scan. It does not open or read the contents of your files. If you confirm Move to Trash, macOS moves that one item to Trash.

What Sundial writes to disk

Sundial writes one saved scan file per scanned folder, under ~/Library/Containers/local.sundial/Data/Library/Caches/local.sundial

Each saved scan file contains:

• the full path of the folder you chose
• the volume identifier
• the date of the scan
• the number of files and folders the scan counted
• one record per folder in the tree, holding the folder's own name, its total size, the summed size of the files directly inside it, its item count, and a link to its parent folder

Individual files get no record. A file's name and its size are never written to disk. The size of the files directly inside a folder is written only as a single sum for that folder.

Sundial writes two preferences, the appearance theme and the selected view, to the app's own preferences store.

Sundial writes nothing else. The filesystem event cursor stays in memory for as long as the window is open and is never written to disk. The hard-link flag, individual file names, individual file sizes, and the folder-picker access grant are also memory only. Sundial does not keep folder access across launches, so it asks again the next time you open it.

Retention and removal

A saved scan file stays until you choose Forget saved scans, until macOS removes cached data, or until you remove the app's stored data. Forget saved scans deletes every saved scan file and stops scans already running in other windows from writing new ones. Scans you start after that can write new saved scan files. A scan already on screen stays in memory until you close its window. The two preferences are separate from saved scans and Forget saved scans does not touch them.

Deleting an item to Trash also deletes the saved scan files for the folders that contained it.

A scan whose folder records exceed 64 MiB is not written to disk. It stays on screen and Sundial tells you it was not saved.

Sharing and network access

Sundial does not transmit your scan data or preferences to the developer or to anyone else. The privacy policy and support links in the app open in your browser, at which point your browser's privacy settings and the destination site's policy apply. Anything you choose to send when you ask for support is outside this app. Avoid putting sensitive folder paths in support messages or screenshots.

Your controls

You can stop a scan, close a window, choose another folder, and forget saved scans. macOS controls which folders Sundial may open. An item moved to Trash can normally be restored from Trash until you empty it. Sundial never empties Trash.

Children

Sundial is not directed at children and collects nothing from anyone.

Policy updates

The policy bundled with each version describes that version's behavior. This page describes the current release. Changes appear here with a new effective date.

Contact

Mathieu Dupuis, Quebec, Canada. Write to sundial@mathd.com with any privacy question, or to ask what data the app holds.