Hello Saxman,

I am having the same problem too. The problem is with the BIOS 1.4.3. As the BIOS on the motherboard cannot be downgraded. The only way is to swap up the motherboard which have an earlier BIOS e.g. 1.1.0 and the USB C dock to external display would work again. 

I just have my motherboard replaced yesterday and everything was working fine, until... Until I restart my computer this morning and upon restart, the computer automatically updated the BIOS again which the USB C dock to external monitor stopped working. 

This is my third motherboard replacement and the problem is not with the hardware but is with the BIOS. IT works on older BIOS version. Dell, Please issue a BIOS update to fix this issue please. 

So a few updates: 

• I am on BIOS version 1.5.1. So it seems the problem is also present in this version, if the BIOS is truly the problem.
• I have had discussions with two individuals from Dell support, once when I reached out on my own, and once when someone saw this post and reached out to me.
  • The first told me that they could not help me, because the dock is an HP and not a Dell dock. I guess I understand this approach, but I am 99% sure this is a problem with the Alienware laptop, as it does not happen with either of the other two laptops I have which I can test on. I may reach out to HP to see what they say, but I'm honestly expecting them to just say "it's not our laptop, so try Dell."
  • The second told me that because everything else on the dock works (the mouse/keyboard/webcam/etc), that the port is fine and there is no problem with the laptop. I don't believe this at all, since I know there's much more technology that goes into tunneling the video signals through the dock to the monitors.

I'm pretty frustrated with this situation, and expected this to work out of the box, since the Alienware port is Thunderbolt 4 capable, and should work fine with a USB-C dock as far as I know (obviously not at Thunderbolt speeds).

My external monitor also stopped working over Thunderbolt when I updated the BIOS on my Alienware m15 R6 to 1.4.3. I don't recall what BIOS version it shipped with, but whatever it was didn't have this problem.

My monitor is a Samsung CJ79 series. It has a couple of Thunderbolt ports, HDMI, DisplayPort, and a couple of USB ports. I have a mouse and keyboard plugged into the USB ports. When I received my m15 a couple of months ago, everything worked fine. The monitor was connected to the laptop with a single Thunderbolt cable, and the display and other attached devices worked fine. After updating to 1.4.3, the monitor no longer works, but the devices attached to the USB ports on the back do. Connecting the monitor with a separate HDMI cable is my current workaround.

Really frustrated with the fact that I can't downgrade the BIOS back to a version that worked. I also tried getting support but was dismissed. I guess I'm stuck with the extra cable until Dell fixes the problem. I won't hold my breath though as it sounds like they have yet to even acknowledge there is a problem.

Same exact issue.  Alienware M15 R6 using a Thunderbolt 4 to an Anker  PowerExpand Elite 13-in-1 Thunderbolt 3 Dock Station.  All the ports work except for the HDMI.  However this Dock Station works perfectly with my other two computers. Please notify me when this is fixed. 

Just installed all of those, nothing changed.

Sorry about the issues you guys are having. I will ask if Chris has any news on this type of issue and the possible fix that could allow Type C to work back on the laptop again. Have you guys at least tried reinstalling the Type C driver? 

Actually try to install all of these?

Intel Management Engine Interface Driver | Driver Details | Dell US

Intel Chipset Device Software | Driver Details | Dell US

Intel HID Event Filter Driver | Driver Details | Dell US

Intel Thunderbolt Controller Driver | Driver Details | Dell US

Installed the first 3 and it didn't fix the problem.   The fourth one wouldn't install because I already had a newer version already installed. Here's what was in the log:

There is a previous driver, comparing versions.
Installed driver version = 1.41.1094.0
Installation driver version = 1.41.1030.0
Installed driver version is higher than In

I'm pretty sure the new driver is not the issue, because I located and found the latest driver to try to fix my HDMI doc issue.

Hello i am having the same issue as everyone else. i have purchased an M15 R6 with 3070 GPU.

I have 2 x Asus tuf gaming VG328H 32" full HD monitors. when trying to connect through a dock it allows Ethernet, sound, key bored, mouse and power connections but will not display on the monitors.

the port obviously works but i can not get display. i have run a HDMI cable from the computer to each screen individually to make sure the screens are working and they are and displaying fine from computer to monitor via HDMI. When using a USB-C thunderbolt 3 to HDMI cable bypassing a dock entirely i still can not get any display on the monitors so the dock is fine and the cable was brand new. is there a setting that needs to change to allow display output via the USB-C ?