LG 5K UltraFine display dark, but charging working

Question

LG 5K UltraFine display dark, but charging working

I have tried to connect my LG 5K UltraFine display to one of our MacBook Pro 14 M2, MacBook Pro M4, and MacBook Air M3 models, all running macOS 26.0.1.

For all the MacBooks, the LG screen suddenly becomes dark, although it does start to charge. I suspected that the Apple 2m Thunderbolt Pro Cable was no longer working, so I bought a 1m Thunderbolt 5 Cable. However, I discovered the same issue.

Has anyone experienced the same and resolved it? This worked like a charm, but then it stopped working sometimes, and eventually it stopped working altogether.

MacBook Pro 14″

Posted on Nov 3, 2025 2:50 AM

Reply

Answer 1

Nov 3, 2025 6:41 AM in response to malcedoniamitsenf

Cables required for running high resolution displays over ThunderBolt are limited to 0.5 meters, maximum length.

If you need more length, you MUST use a (much more expensive, starting at US$125) ACTIVE ThunderBolt cable instead.

Reply

Answer 2

samtenor

Level 4

2,074 points

Nov 3, 2025 6:43 AM in response to malcedoniamitsenf

LG made few versions of this 5K monitor.

Scenario 1: Firmware - you can go to app store and download LG display/monitor via your laptop.

Run the firmware update to see if it will make any difference. (DIY)

Scenario 2: The thunderbolt port may got loose - pretty common on this 5K monitor.

Scenario 3: the control board of the monitor went bad.

On scenario #2 and #3 - you will need to find a shop for the repair after try firmware update.

Best

Reply

Answer 3

Nov 3, 2025 7:06 AM in response to Grant Bennet-Alder

Both my cables are active cables sold by Apple for around 100-150 USD in Retail.

Reply

Answer 4

Nov 3, 2025 10:42 AM in response to malcedoniamitsenf

what exact model number 5K ultra fine display?

Reply