Mac App Store app triggers "cannot verify free of malware" alert when opening as default app

My app Mocawave is a music player distributed through the Mac App Store. It declares specific audio document types (public.mp3, com.microsoft.waveform-audio, public.mpeg-4-audio, public.aac-audio) in its CFBundleDocumentTypes with a Viewer role.

When a user sets Mocawave as the default app for audio files and double-clicks an MP3 downloaded from the internet (which has the com.apple.quarantine extended attribute), macOS displays the alert:

"Apple could not verify [filename] is free of malware that may harm your Mac or compromise your privacy."

This does not happen when:

  • Opening the same file via NSOpenPanel from within the app
  • Opening the same file with Apple's Music.app or QuickTime Player

The app is:

  • Distributed through the Mac App Store
  • Sandboxed (com.apple.security.app-sandbox)
  • Uses com.apple.security.files.user-selected.read-write entitlement

The file being opened is a regular audio file (MP3), not an executable. Since the app is sandboxed and distributed through the App Store, I expected it to have sufficient trust to open quarantined data files without triggering Gatekeeper warnings — similar to how Music.app and QuickTime handle them.

Questions:

  1. Is there a specific entitlement or Info.plist configuration that allows a sandboxed Mac App Store app to open quarantined audio files without this alert?
  2. Is this expected behavior for third-party App Store apps, or could this indicate a misconfiguration on my end?

Environment: macOS 15 (Sequoia), app built with Swift/SwiftUI, targeting macOS 13+.

Mac App Store app triggers "cannot verify free of malware" alert when opening as default app
 
 
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