Mac laptop to TV issue: mirror display doesn't work?
It seems to me that the frequency you have your laptop configured at is not supported by your TV.

When using mirror displays, it usually mirrors your main screen (resolution &amp; frequency). Your main screen would be the one where you have the Dock and Menu bar.

Can I ask why would you want to mirror display on your TV? Is this for watching videos?
If so, I would recommend you to do the following:


Connect your HDMI cable
Click on detect displays, disable mirroring
Install VLC player


With VLC you can use your second screen on full screen mode without the need of mirroring.