Mac System Audio Capture: Fix Permissions When Live Captions Do Not Work
A practical guide to Mac system audio capture, Screen & System Audio Recording permission, and the checks that make live captions reliable.
2026-08-10 · 12 minWhat Mac system audio capture means
Mac system audio capture reads the sound being played by an app, browser tab, meeting, or media player. It is different from recording a room with a microphone: the caption tool receives the digital playback that reaches macOS. That is why it can be useful for YouTube, Zoom, online courses, and calls when you want captions without changing the original app.
Why the Screen & System Audio Recording permission matters
macOS protects playback capture because system audio can contain private conversations, paid media, or notifications. The Screen & System Audio Recording permission gives an app access to the playback stream; it does not mean the app must save screen frames. In Alison Workspace, the permission is used to read system audio for captions and translation, while the exact retention behavior is described in the app privacy settings.
A reliable setup sequence
Install Alison Workspace, open macOS System Settings, then review Privacy & Security and the Screen & System Audio Recording list. Enable Alison, restart it if macOS asks, and choose the spoken language before starting playback. Test with a short browser video at a comfortable volume. A ten-second test catches a disabled permission, the wrong input source, or an unavailable language resource before a long meeting begins.
What to check when Mac live captions are not working
First confirm that the video or meeting is actually producing sound through the Mac, not a disconnected display or Bluetooth device. Then mute unrelated tabs, check that Alison is not paused, and verify that the selected language matches the speaker. If the subtitle bar is empty, quit and reopen the app after changing permission, install the required Apple language resource or local model, and test ordinary browser audio before protected media.
Microphone, protected media, and privacy limits
System audio capture can avoid room echo, but it cannot repair a noisy source or overlapping speakers. Protected media may block or alter playback capture, and some hardware routes audio outside the Mac stream. For sensitive work, tell participants how captions are being used, keep the original audio available, and delete local text history when it is no longer needed. Treat captions as assistance, not a guaranteed legal transcript.
Frequently Asked Questions
Does Mac system audio capture need a microphone?
No. The intended workflow reads the audio playing through macOS, so a room microphone is not required for browser, meeting, and media playback.
Why do captions stop after I change the permission?
macOS may require the app to restart before a new recording permission is available. Quit and reopen Alison, then run a short system-audio test.
Can every protected video be captioned?
No. Protected media and unusual audio routes may limit capture. Ordinary browser, meeting, and media audio is the more reliable test case.