hdmi not working after updating to Catalina 10.15.7

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hdmi not working after updating to Catalina 10.15.7

A few days ago I updated to Catalina 10.15.7. Until then my HDMI cable connection from my Mac mini (Late 2012) to my LG smart TV was working perfectly.

Initially, after the OS update there were frequent dropouts but it was still working (yesterday).

Today all I get on my smart TV is the lovely desktop picture of Catalina Island.

From this I can deduce that somehow my smart TV knows there's a signal coming down the HMDI cable - but I'm not getting the signal.

What is going on and can I fix it? Needless to say I've checked the cable (both ends) and tried various reboots of the TV and the computer.

Posted on May 22, 2022 10:15 AM

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Answer 1

Top-ranking reply

DerekM87

Community Specialist

May 23, 2022 11:15 AM in response to Tom in London

Tom in London,

Do you have another display you can test with and/or a different HDMI cable? It's best to isolate the issue as much as possible.

Also, follow these specific steps to reset the SMC on your Mac mini.

Desktop computers

Shut down your Mac, then unplug the power cord.

Wait 15 seconds, then plug the power cord back in.

Wait 5 seconds, then press the power button to turn on your Mac.

How to reset the SMC of your Mac - Apple Support

If another display works without issue, we'd recommend checking your LG tv to see if it has any software updates, then contact LG directly for support if need be.

If instead, you can confirm its no longer working with multiple displays and the SMC reset does not resolve the issue, we'd recommend contacting Apple Support for assistance.

Apple Support

Cheers!

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Answer 2

Sparks0829

Community Specialist

May 23, 2022 10:53 AM in response to Tom in London

Hello Tom in London,

If you're not seeing your Mac mini desktop as expected on your external display, try these steps:

If your Mac doesn't recognize your HDTV, display, or other HDMI device after making the connection:

1. Turn off the HDMI device while your Mac is turned on.

2. Unplug the HDMI cable from your Mac, then plug it in again.

3. Turn on the HDMI device.

Learn more here: Connect to HDMI from your Mac

Take care.

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Answer 3

Tom in London Author

Level 4

1,638 points

May 23, 2022 2:34 PM in response to DerekM87

Other weird things also started happening - e.g. the Finder going grey on me, the mouse disappearing, etc. So I did something better. I went back to a clone I had made about 4 days ago, and cloned back to where I was before I installed the latest OS update. Hey presto, my HDMI is working again. MORAL OF THIS TALE: always make sure you have a backup of your hard drive before you install any system updates.

I have no idea why I lost my HDMI or why those other bad things were happening. Maybe it actually didn't have anything to do with the system update. Maybe it was something else I did.

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Answer 4

May 24, 2022 8:09 AM in response to Tom in London

Do you have only the TV connected to your mini?

It looks like you have another display, and you used to have the TV mirroring it but not it is working as extended desktop - a second, additional display, instead of a copy of the other one.

This is simple to change.

Press Command-F1 and you are done.

Or, if you don't have an Apple keyboard (in which case the keys above may or may not work), go to System Preferences->Displays->Arrangement and UNcheck "mirror displays".

Done.

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Answer 5

Tom in London Author

Level 4

1,638 points

May 23, 2022 11:01 AM in response to Sparks0829

Nope - thanks but that didn't work.

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hdmi not working after updating to Catalina 10.15.7

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