Mac Studio display connection issues with LG OLED TV

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Mac Studio display connection issues with LG OLED TV

Mac Studio and LG - 55" Class C6 Series OLED

I got the LG TV this past Saturday. I spent Saturday and most of Sunday trying to get the Mac Studio to work together. My current working setup is to use a Thunderbolt display with the LG and to turn video mirroring.. Somehow this makes the video connection to the LG work much more reliably.

The HDMI cable between the Mac and the TV is like 20 years old I think. That's my first suspect. I need to change out that cable for a high performance 48Gbps Ultra High Speed HDMI 2.1 cable. The second is I don't know how the Mac and TV handshake. Previous trials - the Mac video would flash then go to black while showing in Settings > Displays that Mac OS recognized the LG. When working, the images are amazing and I can toggle HDR.

What I'm really asking for is advice in how to properly setup this TV with my Mac Studio. Are there any MacOS settings I need to turn on especially for the LG?

Mac Studio Specs:

M4 Max

48 GB RAM

1 TB drve

Thanks for your help.

Mac Studio, macOS 26.7

Posted on Oct 5, 2026 10:49 AM

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Answer 1

Oct 5, 2026 10:55 AM in response to phabe

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"PREMIUM High Speed HDMI cable" or that + "with Ethernet" (up to 4K at 30Hz) --OR--

“ULTRA High Speed HDMI cable" or that + "48G" (supports higher resolutions and backward-compatible)

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

Cables 'shipped in the box' with many displays can be "lowest bidder" cables that are not up to high-end display use. Cables with no markings 'found' behind your TV set are unlikely to be good enough.

HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.

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Answer 2

Oct 5, 2026 10:56 AM in response to phabe

Display Recognition:

The Mac does not rely on Windows-like side-loaded "Drivers" which are actually packages of resolutions and settings for a specific display. Instead, it goes straight to the immutable source -- it asks the display itself.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own can generally not respond to the Mac's query, and will stay dark.

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