Observe the trigger
If a television works with a Mac laptop open and goes dark when its lid closes, note that exact trigger. Apple’s external-display troubleshooting specifies power and an external keyboard and mouse for the documented closed-lid setup.
A working open-lid desktop is useful evidence that the initial video route functions. Closing the lid changes the computer’s operating arrangement, so investigate that transition before modifying the film or streaming account.
Prepare the intended arrangement
Connect power and the required external input devices, then follow Apple’s current display guidance for the Mac model. Keep the television input and cable route unchanged. Check that the external controls can wake and operate the computer before relying on it for a long programme.
If the screen returns, test pause and exit as well as playback. A closed laptop placed out of reach still needs a practical way for the viewer to control the session.
Report what remains different
If the issue persists, record whether the TV is detected, whether a dock is involved and whether opening the lid immediately restores the image. Review the model’s supported display combinations next.
Do not hide an unresolved state behind a claim that all Mac laptops behave identically. This page explains the prerequisite check Apple documents, without asserting a tested result for a particular laptop, dock or television.
Questions answered
Does closed-lid viewing have additional requirements?
Yes. Apple’s guide specifies power and an external keyboard and mouse for that arrangement.
Why test controls before a long programme?
The viewer needs a usable way to wake, pause and leave the session with the laptop closed.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.