Dell Thunderbolt Dock - WD19TB: external monitor stays black after laptop is locked/put asleep

AFAIK using the dock with two different machines should not be problematic

If the finger sensor is at issue, try enrolling it again

Can I get the model of laptops in use?

@HedgeFundManager​
Laptops are:
Dell Latitude 7420 running Windows 11 Pro (my private one)

Lenovo ThinkPad T14 Gen 1 running Windows 10 Pro/Enterprise (it's my company's computer)

Maybe I wasn't precise - at any specific moment I only use one laptop connected to the dock through the docks thunderbolt cable. By mentioning two laptops, what I meant was that problem with waking up the monitor (visible by system, but the screen remains black like turned off) is laptop agnostic - it happens on them both, so I assumed the problem is with dock firmware. 

Fingerprint sensor is another issue, enrolling it again works only for that "session". After I turn Dell laptop off the issue is still there. I made a post for this:
https://www.dell.com/community/en/conversations/latitude/fingerprint-reader-doesnt-recognize-fingerprint-on-dell-latitude-7420-with-windows-11-pro/673e3812658f90008b71880f

The old T14 gen 1 is a 10th gen Intel CPU, the Dell is 11th Gen so its slightly more recent. Either machine should be fine as both have TB3 support.

I use a Dell Latitude 5440 (13th gen Intel) which I bought using facial recognition and so far its not at problematic.

The T14 has a finger sensor and is it at issue like your Dell machine?

@HedgeFundManager​ Both laptops have issue with Dell monitor "not waking up"/staying blank when connected to WD19TB dock - which is main problem here. They worked perfectly fine since February 2024 until dock's firmware update at the end of November 2024. I brought fingerprint reader issue only as one of the methods I used to wake up the laptops - problem with blank monitor doesn't seem to be connected to fingerprint reader issue on Dell Latitude 7420.

Fingerprint sensor is faulty only in Dell Laptop, but solutions provided in other threads (reinstalling Dell-ControlVault3-Driver-and-Firmware) didn't work. Sensor was working until October/November 2024 update of Windows or something from Dell through Dell Command and Update app. Now I use only facial recognition, but it doesn't solve the blank monitor problem...

I am having this exact same issue.  If the computer goes to sleep or is locked, then I will have to cycle power on the monitor (power button) in order to be able to use the monitor again.

This system worked perfectly with no issues until the firmware update in November 2024.

As R3TZ3V stated, this issue appears to be computer-agnostic, but the model of computer I am using is a Precision 3581.

Cycling power on the monitor is a workaround that works every time, but it's very frustrating that an update which is supposed to fix things has introduced this new issue that I have to deal with maybe a dozen times per day.  A fix for this sooner rather than later would be appreciated.

@R3TZ3V​ The Dell Controlvault is an expensive option with Dell while Lenovo is more uniform. My old T14 developed a motherboard fault so I grabbed this Dell Latitude 5440 to replace it.

Now docks vary somewhat depending on capabilities etc so I am suggesting disconnecting the dock, reboot the laptop a few times and then reconnect the machine.

So far on my 5440 the mug shot seems to work fine, My old XPS 15 9570 needs a new finger board to be installed.

@HitmanHart​ Most monitors use EDID signalling and this does not flow back to the laptop reliably with many different dock solutions I have tried.

So far nothing has changed from Dell side (no firmware changes to the Dock or the monitor), but one of described by me methods seems to work most of the time:
I press key kombination: Ctrl+Shift+Win+B and before I press it, I move mouse cursor onto the "black" monitor - but this might be irrelevant placebo ;-)

(Almost) the same problem here, a lot of people with Latitudde 5450 and Latitude 7350 (not older models) have this same problem. when waking up one screen stays black, but exists in Windows, so you can tab to items on it, the other screen goes on (backlight on) but only shows the white mousepointer which can be moved.
Some of the users have the Dell WD19S dock, others use the dock in the Dell P2422HE monitor.
My colleague uses this setup and even laptop whith Linux installed show the same problem, so it is not Windows  (11) only.
Since various hardware and different OS's seems to be affected it looks like Laptop firmware might be the culprit,

I found my USB4 port can handle displayport 2.0 at 8K60 HBR10 suggesting docks leave something off the table for full support for USB4 and TB4.

There was a firmware update for my dock recently (most probably installed through Dell Command | Update around 6th of May) and since then I no longer have problems with black screen after waking up on both laptops I've been using dock with. 

Most docks I have tested lack full USB 4.0 support.

I have created a call with Dell support for this issue. <Private data removed from public view. DELL-Admin>

The mentioned workaround works for us (pressing Ctrl-Shift-Win-B), it restarts the display drivers and both screens come back to life.
I have tried the latest Latitude firmware and the latest display drivers and the latest firmware for the docks, but the problem remains. (firmware downloaded manually from the support website)

I send the Logs to Dell, they are investigating this as a structural issue and not a single workstation incident.

Similar issues here with two monitors connected to the USB-C ports in the back.

The problem is specific to the TB output on the dock (the one to the side)

All Dell gear:

Latitude 5531

WD19TB

2 * P2419HC displays

Started after the last update I did on July 15th.

Unplugging and replugging did the trick so far, but I'll try the slightly more practical crtl-shift-win-b.