Built-in monitor goes black on disconnect of external monitor from Thunderbolt

[OldDzik]

I have Samsung Odyssey 32" connected on Thunderbolt. It used to work fine. However, some time ago it changed.

Now, the built-in monitor goes black when I disconnect external monitor from Thunderbolt. As if both screens were disconnected and the computer did not switch to single monitor configuration.

Strangely, connecting the external monitor back to Thunderbolt restores image on both screens: external and internal.

Can anybody help?

[BeemerBiker]

Probably a hardware problem.   When the screen is blank, shine a light into it and see if anything is visible.  If so, the the backlight is at fault and something is turning off it's power.

With both screens press the windows key + P and select "The PC screen only".  Do both screens go blank?

If not, then disconnect from the thunderbolt port.  Did the laptop go blank?

According to the manual you have two USB-C ports: the ones numbered "2" although the forms are different.

USB Type-C power connector and Thunderbolt™ports with HP Sleep and Charge (2)

Can you try the other port?

Are you using a docking station?

Does the problem occur both on A/C power and Battery?

Does the laptop work OK if you power it up with the external monitor disconnected?

Are you charging the laptop through the other USB-C port?

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[OldDzik]

Hi! Thanks for your response!

So using Win+P works fine to select "Duplicate", "Extend" or any "External monitor", but when I select "Built-in monitor only" - all displays go black. Pressing Win+P in the blind - restores "Duplicate" configuration and they work again.

The same happens on both USB-C ports, battery or AC.

I tried another external monitor (using USB-C to HDMI and to Display Port) and the behavior is identical.

I don't use any hub or dock.

When powered-up without external monitor - laptop works fine.

I did run HP hardware diagnostics, including Thunderbolt troubleshooting, with no issues detected.

Could it be Windows? All updates are installed...

Best regards

Pawel

[BeemerBiker]

It could be a windows bug.  You can test to see if windows related by projecting your laptop onto another device such as a smart TV, roku, another laptop, AIO or even a desktop that has WIFI

You can project your laptop to any WiFi enabled system:  This link here gives instructions on adding a laptop to desktop as a monitor or vice-versa using Wi-Fi.   Android can also do this as shown here
Once you are projecting on the screen you can select "mirror" or "extend"

Then select "The PC screen only" and see if your display goes blank.

I looked here and did not see anything related to fixing an external monitor problem.

Do not update your BIOS unless the HP support assistant requests it.  There is the risk, however small, that a bios update can go wrong and the system become unusable.  Run HPSA and see if it recommends any type of update

Another thought:  are you running 3 desktops, not just 2?  Possibly when selecting "The PC screen only" your system is switching to the 3rd desktop which is blank.

When the screen goes blank try one of the following "swaps"

https://www.howtogeek.com/688174/how-to-quickly-switch-between-virtual-desktops-on-windows-10/#:~:te....

try the windows key plus CTRL plus the left or right arrow

[OldDzik · Accepted solution]

Hi again!

So installing new Intel drivers for iris fixed the problem. Still don't know what caused it, but I downloaded drivers from here:

Link to Intel drivers 

and monitors switching works fine again. Found the hint on reddit, of all places

Pawel

[BeemerBiker]

There is a problem with that link. 

You need to reverse the "text" and the URL

Should be something like this

This is helpful as the problem shows up frequently.