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Serial Port
Posts: 12
Registered: ‎05-26-2019
Location: CA
Views: 2,073
Message 1 of 2

New ThinkPad USB-C Dock constant disconnect from X1 Carbon G6; widespread issue?

When powering my X1 Carbon Gen 6 via my new ThinkPad USB-C Dock Gen 2 (40AS)the dock will frequently disconnect and then rapidly reconnect to the PC.


  • When the dock disconnects, all connected devices are also disconnected from the PC, including USB and ethernet.
  • However, the dock remains powered on with a yellow light, and delivers power via the powered USB port.
  • When the dock disconnects, it and all attached devices show a yellow hazard triangle in the device viewer, before vanishing and reappearing once they connect.
  • This all happens within a span of seconds, usually repeatedly, and most often when the fans are spinning up.
  • Sometimes when disconnecting, the dock light will turn yellow, will make a loud "clicking" sound similar to a mechanical hard drive. This happens most frequently when disconnecting a secondary power source (see below).
  • The drivers and firmware for both the X1 and the dock are up to date.


The only "solution" I've found is to connect both the 65w adapter that came with the X1 and the USB-C cable connecting to the dock that's being powered by the included 90w adapter. This seems to provide enough power to prevent devices from disconnecting. However, I've noticed that once both are plugged in, removing the X1 adapter while the dock is still connected will immediately cause the dock to start disconnecting and repeating rapidly. And of course, I bought this dock so I could do everything through one cable, not two.


Everything seems to point to either the dock not providing enough power to the machine, or the X1 failing to manage to the power properly.


I would have assumed this was a hardware issue and returned it for an exchange already, but I found several similar threads about the X1 Gen 6 with different docks, both Lenovo and non-Lenovo. This post was particularly interesting:


"I've tried an X1C5 in the same dock and no problems occur whilst using my X1C6 on 4 different 40A9 docks reveals same issues."


After installing all of the software recommended by Lenovo staff in those threads, nothing really changed. Wondering if I should return while I can.


Since both my X1 and the dock are brand new, this seems to be a still-ongoing issue that deserves some renewed attention. Posting this thread in the hopes that someone from Lenovo can spot this and help find a solution. This is my first ThinkPad and I really love it, but this issue in particular has been really frustrating.

What's DOS?
Posts: 2
Registered: ‎09-22-2019
Location: CA
Views: 1,185
Message 2 of 2

Re: New ThinkPad USB-C Dock constant disconnect from X1 Carbon G6; widespread issue?


I too have a gen6 X1, and usb-c (gen2) dock. 


I found my mouse and keyboard do not work if the USB-c cable is connected to the usb-c port towards the back of the computer. But they work fine if connected to the USB-c port close to the front of the computer (towards the user).


However, any powered USB devices (smart phone, powered external harddrive) work without any issue connected to the dock regardless of which USB-c port the dock is using connected to the computer.


This is very likely a power issue with the dock.


See some discussion in this thread:

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