Black screen when recording on a Mac

The recording plays back as a black rectangle with correct audio and correct length. macOS is withholding the screen picture, not iRecord.

Cause. Screen Recording access is not granted to iRecord, or it was granted while iRecord was already running. macOS hands the screen to an app at launch, so a grant made mid-session does not reach the copy that is running.

Fix

1. Open the New Recording window.
2. If the row Screen Recording access needed is showing, press Grant. It opens System Settings at Privacy & Security → Screen Recording.
3. Turn iRecord on in that list.
4. Quit iRecord and open it again.
5. Start a new recording. The Record button is disabled until the permission is actually in place, so a black take cannot be started by accident once step 4 is done.

A take already recorded black cannot be recovered — the picture was never written to the file.