RecordingFixes5 October 2026·2 min read

Your iPhone demo records as a black rectangle: how to fix it

Tella's own tip page says AirPlay mirroring records as a black rectangle. The cable-and-QuickTime route that works, step by step, and how to record that window with Prequel in Window mode.

Musthaq Ahamad

Building Prequel

You mirrored your iPhone to the Mac to record a demo, started the recording, and got a black rectangle where the phone should be. Tella documents it. The fix works in any recorder.

What Tella says

On its tip page for iPhone demos, Tella's help centre says "AirPlay mirroring records as a black rectangle". The route it gives is to connect the device by cable and record a QuickTime Player window instead.

Show the phone through a cable

This is how the Mac's own QuickTime Player does it.

1. Connect the iPhone to the Mac with a cable and unlock it. Tap Trust if it asks.
2. Open QuickTime Player and choose File, then New Movie Recording.
3. Click the small arrow beside the record button.
4. Under Camera, choose your iPhone. The phone's screen appears in the window. You now have a normal Mac window showing the phone. A normal window is the thing screen recorders can record.

Record that window

Do not use QuickTime's own record button for the demo unless you want a plain file. Record the window with a recorder that can zoom and frame it.

In Prequel, choose Window on the dock. The screen dims and the window under your pointer is highlighted with its app icon and name. Click the QuickTime window, then press Start recording. See sources.

In the editor you can place the phone on a background, add zooms, and add your own camera in a corner with one of the layouts: see layout and zooms.

Making the phone look right

• Turn on Do Not Disturb on the phone first, so no banner crosses the demo.
• Resize the QuickTime window to the phone's proportions before you record, so the frame is not mostly empty.
• Check the sound with a 10-second test. The iPhone's microphone and the Mac's are different devices, and why screen recording audio drifts out of sync explains what happens when two devices disagree.

A related tool-specific limit is Tella is not recording computer audio. For the limits on what Tella lets you change afterwards, see what Tella's editor can't do after you record, and for audio sync, Tella audio out of sync.

The general guide to recording on a Mac is the complete guide to screen recording on Mac, and before you press record has the checklist.

Record the QuickTime window in Prequel and place the phone on a background.

Prequel needs an Apple Silicon Mac on macOS 14 or later. Download Prequel for Mac and try it free for 7 days, with no watermark on anything you export. After that it is $9 a month or $29 once. See what it costs.