How to resolve 'no signal found' message on Ultragear monitor connected to 2026 Mac mini via USB-C cable?

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How to resolve 'no signal found' message on Ultragear monitor connected to 2026 Mac mini via USB-C cable?

I was running a 2025 Mac mini to an Ultragear monitor through USB-C for a year and no issues whatsoever.

I brought the monitor home and connected it with same USB-C cord to a brand new 2026 Mac mini. I am now getting a message stating “no signal found” and monitor goes to sleep. I have tried a different USB-C cable and an HDMI cable. Nothing works.

However, when I plug in the monitor to the Mac mini is lights up the monitor so it seems to recognize it, but then the dreaded no signal found message appears.

Help?!?!

[Re-Titled by Moderator]

Original Title: No signal found message

Mac mini, macOS 15.6

Posted on Feb 6, 2026 5:02 AM

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Answer 1

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den.thed

Level 10

93,734 points

Feb 6, 2026 7:22 AM in response to shawn171

What model and size is the LG UltraGear Display..?

1) Test a different Display or HDMI TV connected to the new 2026 Mac min at home.

2) Test an Apple Thunderbolt 5 (USB-C) Pro cable or a short high speed 8K HDMI 2.1 cable.

3) Use the manual controls on the LG UltraGear Display to home-in on the USB-C or HDMI input.

4) Work thru the pertinent steps at > If your external display is dark or low resolution - Apple Support

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Answer 2

Feb 10, 2026 2:52 PM in response to shawn171

shawn171 wrote:

LG 45GR75DC-B Ultragear Curved Gaming Monitor 45-Inch

LG – 45 Inch UltraGear™ QHD 1440P 1ms 200Hz Curved Gaming Monitor with USB Type-C™

That monitor has a resolution of 5120 x 1440 pixels, and a refresh rate of 200 Hz.

It has several video inputs:

(1) USB-C (DisplayPort Alt Mode) input
(2) HDMI 2.1 inputs
(1) DisplayPort input

The Technical Specifications for the M4 and M4 Pro Mac minis do not promise support for that combination of resolution and refresh rate, especially over a plain USB-C (DisplayPort) (not Thunderbolt) connection. You will probably need to live with a much lower refresh rate.

5120x1440 pixels is slightly fewer than 3840x2160 pixels, so a plain USB-C (DisplayPort) connection should have enough bandwidth to support running the display at 60 Hz.

If the monitor supports a Picture-by-Picture mode, you could try running two video cables to it, with each half (Left, Right) looking like a 2560x1440 monitor to the Mac. If that worked, you could use extended desktop mode to re-combine the separate halves into one continuous workspace.

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Answer 3

den.thed

Level 10

93,734 points

Feb 8, 2026 10:20 AM in response to shawn171

You should use a short 3.3' 8K Certified Ultra High Speed 2.1 HDMI cable with the setup.

for example: https://www.amazon.com/gp/aw/d/B0CQP27WZ2/?

Or optionally an Apple Thunderbolt 5 (USB-C) Pro cable with that setup.

https://www.apple.com/shop/product/mdw94am/a/thunderbolt-5-usb%E2%80%91c-pro-cable-1-m

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Answer 4

Feb 10, 2026 2:30 PM in response to shawn171

Make sure that you are using the rear-panel USB-C ports on the Mac mini.

The rear-panel USB-C ports on the M4 and M4 Mac minis are full-fledged USB / USB4 / Thunderbolt ports, which support a number of protocols, including DisplayPort Alt Mode and Thunderbolt-encapsulated DisplayPort.

The front-panel USB-C ports are USB-only ports which do not carry any form of video signal.

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