LG 4K monitor reports that supplied cables should be used

I bought a TBT3-UDV about a month ago, but only yesterday tried it with a 4K monitor and it reports this message most times I connect the laptop:

Half the time it wouldn’t even connect and I can see the second display cycle in Windows configuration as it appears and disappears, as if the cable connects and disconnects. Once connected, though, it stays connected and just shows this message.

It’s as if some of the DisplayPort parameters produced by TBT3-UDV are not up to their nominal values.

My Setup:

  • The monitor is LG 27UD59P connected via the shipped DisplayPort cable
  • The computer is HP Spectre x360 Convertible 13-ae0xx running Windows 10, fully updated with Windows and HP updates.
  • TBT3-UDV connected via the shipped Thunderbolt3 cable

Some of the troubleshooting steps I took:

  • My laptop comes with a TB/HDMI dongle. When I connect the monitor via that dongle and the HDMI cable, the monitor doesn’t complain and everything works as expected
  • When I use the DP/HDMI converter that comes with TBT3-UDV and connect the monitor via TBT3-UDV/HDMI cable, I see the warning message above
  • I read in a few discussions in these forums that powering down TBT3-UDV would reset it and tried all of the above with powering down TBT3-UDV and there was no positive effect
  • Updated my laptop BIOS to the latest supplied by HP and tried all of the above again and it still doesn’t work.

Hi Andre,

Thank you for posting! I am sorry things are not working as expected with your new docking station and I would be happy to help.

Thank you as well for the detail you provided and the troubleshooting you have already performed that is much appreciated. The behavior you describe is not expected nor have we had any similar reports, so we are in somewhat uncharted territory (the warning message you received is not even mentioned in the monitor’s manual from LG).

A quick question for you…if you select the ‘Do not display this message again.’ option from the cable notification message and then OK the change, does that change the behavior?

Thank you,

Plugable Technologies

I didn’t want to hide it before I came to some resolution and, what’s more importantly, because it appeared to be cycling display connect/disconnect in some conditions, which seemed as if there is any protocol or electrical incompatibility. I will try again in the next couple of days to see if I can provide more details on this cycling. From the user’s perspective, it looked like the monitor appeared for a second and then disappeared in Windows 10 setting. I will also check if there’s anything in Windows event logs and will post an update tomorrow.

If there’s any tool that can capture the interaction between the computer and the Thunderbolt port, similar to how Wireshark can capture USB traffic, I can run that. Let me know.

Hi Andre,

Thank you for getting back with the update, I appreciate the additional detail you provided.

Another quick question for you, can you confirm that you are using only the Thunderbolt 3 cable we included in the box with the dock to connect it to the system? I ask because other cables can sometimes cause problems.

In addition to that confirmation, just after the behavior has occurred please keep everything connected (even if the monitor may not be working) and send the output of our diagnostic utility PlugDebug –> http://plugable.com/support/plugdebug to us directly at support@plugable.com with ‘For Ticket # 241645’ in the subject line. This will allow us to match things up and examine some log files from your system to help determine the next steps. ** Please do not post the PlugDebug file in our public forum **

Please also include in your email a screen shot (http://www.take-a-screenshot.org/) of the Thunderbolt 3 ‘Details’ information from your system by following the steps under the “How do I check which version of Thunderbolt 3 software and NVM firmware I am running in Windows?” from this link -> http://plugable.com/thunderbolt-3/support

Thank you,


Bob and I did a bunch of troubleshooting via email and I installed a few HP updates in the process and wanted to update this thread for anyone else who may find this useful.

Overall, I encountered three problems listed below:

1. The monitor displayed a note that only supplied cables should be used.

I could swear that when I originally connected my laptop via an HDMI dongle that came with the laptop, there was no message, but when I connect the laptop this way to the display again now, I do see the same message. I don’t know if all of the updates I did on the laptop changed something or I missed this message somehow in my initial testing, but there is no way to verify this now without a full bare metal restore. One thing is clear, however, it’s not caused by TBT3-UDV.

2. The monitor would half the time go into a weird connect/disconnect cycle indefinitely

This one is caused by a compatibility problem between TBT3-UDV’s charging TB port and the laptop. Once I connected TBT3-UDV to the laptop via the non-charging port, the monitor started to connect properly time after time. It’s not ideal because I have to connect both cables - one for the HP charger and one for TBT3-UDV, but I will take it.

3. Every time I connect TBT3-UDV, I would get a message that a a USB device is not recognized

An unknown device was listed as a problem device in the Device Manager as well. This was also caused by compatibility between TBT3-UDV’s charging port and the HP laptop. Just as with issue #2, connecting via the non-charging TBT3-UDV port solved this problem.

You can close this thread. I will just keep using the non-charging TB port. Thanks for your help.

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