Thunderbolt4 dock stopped functioning after upgrading from Windows 11 25H2 to 26H2

Didier 5 Reputation points
2026-10-21T08:30:08.7866667+00:00

After upgrading from Windows 11 25H2 to 26H2 on October 20, 2026, my Lenovo ThinkPad Universal Thunderbolt 4 Dock (40B0), previously working normally, stopped functioning completely.

This is not just a Lenovo Dock Manager detection issue:

  • The dock's power button LED is yellow instead of its usual white.
  • Lenovo Dock Manager reports that no Lenovo dock is connected.
  • All dock-connected functions are unavailable: USB peripherals, HDMI display, Ethernet, laptop charging.
  • The USB peripherals and display work normally when connected directly to the laptop.
  • Device Manager reports both USB4 Host Routers as working properly, using Microsoft driver version 10.0.26100.9549.

The failure started immediately after the Windows 11 26H2 upgrade. The symptoms suggest that the Thunderbolt/USB4 connection between the laptop and the dock is no longer being established correctly, although I have not yet identified the cause.

Has anyone experienced a similar complete loss of Thunderbolt/USB4 dock connectivity after upgrading to Windows 11 26H2?

Maybe you need more technical environment information :

  • Lenovo Thinkpad P14s Gen 4
  • 13th Gen Intel(R) Core(TM) i7-1360P (2.20 GHz)
Windows for home | Windows 11 | Install and upgrade
0 comments
Answer recommended by moderator
Didier 5 Reputation points
2026-10-26T14:16:37.6566667+00:00

Hi,

I got the right things back thanks to Lenovo support.

I got the white LED back by:

  • completely disconnecting the docking station (which was already done)
  • uninstalling all USB4 and Thunderbolt drivers, including the hidden ones
  • restarting the laptop
  • downloading the "Lenovo USB3.0 LAN Driver for Docks, Adapters and Monitors" (dated July 6, 2026) from the Lenovo drivers site and installing it
  • restarting the laptop
  • powering on the docking station and connecting the Thunderbolt cable to the PC => the LED turned white.

Moving the USB, HDMI, and RJ45 connections over to the docking station, everything is working back as usual.

As far as I’m concerned, this issue is resolved.

Have a great day, everyone.

Was this answer helpful?

2 people found this answer helpful.
0 comments

4 additional answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Panayiotis Palmiris 0 Reputation points
    2026-10-22T22:48:07.81+00:00

    os build: 26300.9711

    Have same exactly problem with windows 11 26H2 and lenovo T480s. Thunderbolt firmware not recognized.

    Was this answer helpful?

  2. TaoLi 119.7K Reputation points Independent Advisor
    2026-10-22T13:53:11.6033333+00:00

    Thanks for confirming. Could you test the dock on another Thunderbolt-capable laptop using the same cable and power adapter? This would help narrow down whether the problem follows the dock or is specific to your laptop.

    Was this answer helpful?

    0 comments
  3. TaoLi 119.7K Reputation points Independent Advisor
    2026-10-21T13:43:13.03+00:00

    Thanks for checking. The next step I’d try is reinstalling the USB4 controllers:

    Disconnect the dock >> open Device Manager >> right-click each of the two USB4 Host Router entries >> Uninstall device.

    Restart the laptop, then reconnect the dock after signing in. This lets Windows detect the controllers again and reload their drivers.

    Was this answer helpful?

  4. TaoLi 119.7K Reputation points Independent Advisor
    2026-10-21T12:08:37.0133333+00:00

    Try fully power-cycling the dock: shut down the laptop, disconnect the dock from it, then unplug the dock’s power and all peripherals. Wait one minute.

    Reconnect the dock’s power first, then the laptop. Turn it on and check whether charging returns before reconnecting peripherals.

    If it still fails, please share the Windows build shown in Win + R >> winver.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.