[macOS 26.5.2][26.721.41059] Codex dictation consistently fails with "Unable to transcribe audio" while ChatGPT Classic works

Summary

Voice dictation in the current ChatGPT/Codex desktop app records audio but consistently fails at the transcription stage with:

Unable to transcribe audio

ChatGPT Classic dictation works on the same Mac and ChatGPT account. This isolates the failure to the new ChatGPT/Codex desktop app or its transcription path rather than the microphone.

Environment

• Product: new ChatGPT desktop app, Codex view
• App version: 26.721.41059
• App build: 5848
• Authentication: ChatGPT sign-in, not API-key auth
• Hardware: MacBook Air M1 (arm64)
• macOS: 26.5.2
• Comparison app: ChatGPT Classic 1.2026.184

Steps to reproduce

1. Open the new ChatGPT desktop app and switch to Codex.
2. Open any task, including a new empty task.
3. Start dictation using the microphone control or Ctrl + Shift + D.
4. Speak for 3–5 seconds.
5. Stop recording and wait for transcription.

Actual behavior

• Recording starts normally.
• No transcript is inserted.
• The app displays Unable to transcribe audio.
• The failure is consistently reproducible with short recordings.

Expected behavior

The recording should be transcribed and inserted into the Codex composer as editable text.

Troubleshooting performed

• Microphone access is granted.
• macOS system dictation works.
• ChatGPT Classic dictation works on the same machine and account.
• Restarting the new app and testing a new empty task did not help.
• The installed app matches the latest production version available at the time of reporting.

Request

Please investigate the transcription path in ChatGPT/Codex desktop 26.721.41059 on Apple Silicon, including any difference from ChatGPT Classic. Please also expose the underlying transcription error code instead of only showing a generic message.