UD-ULTC4K triple 4k dock Apple M2 Macbook repeated disconnects

Hi, I have seen this issue reported in this forum numerous times, but have never seen a solution posted. I have a less than 2 year old UD-ULTC4K dock that was working fine with my 2019 Intel Macbook Pro and my 3 external monitors. It’s a fantastic dock when it works. However, after upgrading to a 2023 M2 Mac, sometimes the dock just keeps disconnecting (from all 3 monitors) and reconnecting every few seconds, making the dock useless. It is impossible to do any work when the screens keep flashing off and on and the network connection keeps switching. I have found that this happens only when the battery on my laptop is below about 80-90%. Plugging the laptop into an external AC adapter or the PD port on the front of the dock (in addition to the main dock connection) stops the disconnections. So it is apparently related to the charging voltage the dock is delivering.

My question is, since this seems to be a well-known issue, will we ever see a firmware upgrade for it? This was a fairly expensive dock that is still sold as compatible with “MacOS 11+” and it doesn’t seem right that I need to use a workaround to use it at all.

Note that this is not the same issue as the DisplayLink monitors disconnecting occasionally; this affects all 3 monitors and all dock connectivity. I suspect this may also affect other Apple Silicon Macbooks (M1).

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Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

At this time there are no known issues that would be causing this behavior with Apple M series Macs, however, there may simply be something wrong with your particular docking station that was just not apparent with the older Intel Mac being used. Your new Mac could possibly be drawing more power and it’s now causing the dock to become unstable with the change in power load. There could even be a problem with the dock power adapter itself rather than the dock, but it’s hard to know for certain without being able to test with a different power adapter.

If using an external charger that would cause the Mac to automatically switch to charging from there rather than through the dock. If connecting to the dock’s front 20W C port that may also trigger the Mac to change charging sources from the rear to the front (although please note this is not recommended to connect the front port to the Mac, as that port is only designed for accessory devices).

Regarding firmware, we do not have a firmware update for this kind of behavior but it should not be necessary.

I would suggest we have you contact us directly via email at support@plugable.com so we can collect some information from you and then help to arrange a replacement since you should still be within our warranty.

Please email us and refer to ticket 432993 in the subject line so we can match things up. When you email us please let us know your Amazon order ID number or other proof of purchase, serial number off the bottom of the dock, and your full name and preferred shipping address. Do not post this information here.

I can then reach back out and provide tracking information once a replacement has been sent.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

A post was split to a new topic: UD-ULTC4K Disconnects and Reconnects

Thank you, the new dock seems to be working properly. I appreciate the warranty and the fast and easy replacement process.

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