Expertbook B9400CEA: No signal to external monitor through USB-C / thunderbolt connection

  1. System: Windows 11, Firmware 311
  2. Battery or AC:
  3. Model: Expertbook 9400CEA
  4. Frequency of occurrence:
  5. Reset OS:
  6. Screenshot or video:


Detailed description:I have a LG 29" monitor with both HDMI, DP & USB-C input ports at the back. I can connect it to my expertbook through the HDMI port no problem, but when I use the USB-C to thunderbolt connection, the external monitor does not receive any signal.

The monitor can detect that I've made a physical connection with the thunderbolt, and asks if I would like to switch from HDMI, but when I do switch, there is a black screen with no video input.

On the laptop end, it can also sense that I've connected the thunderbolt to a monitor, as the charging icon shows up over the battery, but I cannot get any video to display on the external monitor if I specificially select screen mirror / extension.

I've ensured all the USB controller & hosts drivers on the laptop is up to date, but the problem persists.

Any advice?


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