I have a MacBook Pro and regularly connect it to a Samsung TV via HDMI.

Suddenly, it has stopped working - when I connect the cable the screen looks like it is about to share, then comes back. To my knowledge, I did not run a software update.

I have tried 2 different cables (one with, one without USB-C multi adaptor [not apple], both which worked in the past (and the multi adaptor is recognised when external hardrives plugged in instead) . Tried both thunderbolt ports.

This is clearly a Mac issue. I tried resetting the NVRAM - all that happens is the screen intermittently turns on and off whilst I hold down the keys (is this correct?)

Anyone know how I could fix this issue?? Many thanks!

  • You say it’s “clearly a Mac issue”. Did you confirm that the input to the Samsung TV is still working and if so, how?
    – Allan
    Mar 31, 2020 at 8:26

1 Answer 1


In System Preferences > Displays > Arrangement > turn Mirroring on or off, whichever it wasn't set at.

Then resetting the NVRAM again https://support.apple.com/en-us/HT204063

and the last opportunity is to change the Mirroring back to what is was before and reset after that the NVRAM again.

I hope I could help you..

  • Thanks for the suggestion! Unfortunately that did not work. I notice that if I click "detect displays" it briefly swaps to the apple loading screen. Also when loading, at this precise point the screen flickers.
    – erb
    Mar 31, 2020 at 19:23
  • seems strange to me ... have you already tried a other device than the samsung tv? Mar 31, 2020 at 19:30
  • I haven't got one unfortunately, but I did swap HDMI ports on the TV. I still think it is a Mac Display issue however, as when I am repeatedly trying to display share, I lost some content on the browser page I had open. (i.e. I was on Whattsap web and some contact disappeared unless I opened the same chat again)
    – erb
    Mar 31, 2020 at 20:04
  • Also this could be most important: I can get it to work, but it seems to depend on a "stable" (physically) connection.... so if I move the computer it drops....then sometimes reconnects..... but most often doesn't. But this is strange as I have tried two different cables, and both thunderbolt ports - so what I am seeing is similar to a cable issue, yet can't be.
    – erb
    Mar 31, 2020 at 20:04
  • very special. So you can rule out that it is due to the hdmi cable, the thunderbold connection or the samsung screen ... hmmm Mar 31, 2020 at 20:11

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