SentryScreen 0.4.2

Security follow-ups from the 0.4.1 review. Upgrading from 0.4.1 keeps the Screen Recording permission.

• Stuck covers no longer turn protection off. If the small covers fill more than 90% of the screen for over a minute, only those covers lift, for 10 seconds; window covers and detection stay on. Before, every cover was cleared and protection paused for 5 minutes, which could be triggered on purpose. Each lift is written to the parent alert log.
• Window covers say how to close them: "Content blocked — click here, then press ⌘W to close."
• The detection model is only ever loaded from the copy the installer prepares. If that copy is missing or damaged, the background watchdog rebuilds it and restarts protection within about a minute. The app no longer prepares a copy in the account's own folders, where it could be swapped.
• Removing SentryScreen from the app now runs the removal script with a clean, fixed environment.

Install: download SentryScreen.pkg and open it. Signed and notarized by Apple. Checksums are in SHA256SUMS.txt.

SentryScreen 0.4.1

Security and privacy fixes. Recommended for everyone on 0.4.0; the installer upgrades in place and keeps your settings and the Screen Recording permission.

Install: download SentryScreen-0.4.1.pkg below (Developer ID signed and notarized) and open it from an administrator account.

• A standard account can no longer stop protection from starting by putting a
  special file (such as a named pipe) where the app writes its logs. The app
  now skips any log file that is not a plain file and starts anyway, and the
  background watchdog moves the bad file aside and records it as tampering.
• The watchdog no longer changes permissions on a log folder after handing it
  to the user, which a user could have redirected to another file.
• If macOS refuses to hide the app's own covers from screen capture, the app
  keeps retrying every 30 seconds instead of giving up, and records the failure
  so it shows in the parent's status and in diagnostics.
• The parent's view of another account now says "detector failing" when
  detection has stopped working there, instead of "protecting".
• Docs: the privacy section names the developer-only option that saves image
  crops (never used by the installed app); the diagnostics page says plainly
  that two reports from the same Mac can be matched by their contents; the
  install-from-source steps include the setting an ad-hoc build needs.
• The package now includes the full Apache License 2.0 text for the YOLOX-based
  detector.

Verify the download: shasum -a 256 SentryScreen-0.4.1.pkg (compare with SHA256SUMS.txt) and spctl -a -vv -t install SentryScreen-0.4.1.pkg (source=Notarized Developer ID).

SentryScreen 0.4.0

The first open-source release of SentryScreen: free, on-device, AGPL-3.0.

Install: download SentryScreen-0.4.0.pkg below and open it from an administrator account. It is Developer ID signed and notarized by Apple. Requires macOS 14 or later; tested on Apple silicon with macOS 27 (Intel and macOS 14–26 build but are untested — reports welcome).

What's in it

• Free: no license, trial, account or subscription.
• Nothing leaves your Mac unless you choose to send a diagnostic report, which you review in full first (docs/diagnostics.md).
• No root helper and no auto-updater; new versions arrive here on GitHub Releases.
• The tuning tools (Settings › Developer, detection view) are in every build.
• "Uninstall SentryScreen…" is always reachable from the popover and the Setup window.

Verify the download

shasum -a 256 SentryScreen-0.4.0.pkg   # compare with SHA256SUMS.txt
spctl -a -vv -t install SentryScreen-0.4.0.pkg   # source=Notarized Developer ID

Full notes: CHANGELOG.md. Found a missed or false cover? Open an issue — never attach explicit images.