After Windows 11 update, my computer no longer detects extended display

mallory 20 Reputation points
2026-06-10T09:52:40.42+00:00

I have a Dell XPS 15 9510. I tried connecting my laptop to my LG TV via HDMI. I use a USB-C adapter to connect HDMI to the laptop.

After a few attempts of unplugging and plugging into different ports, along with testing other HDMI-connected devices into the tv (they work fine), I got a red text message in the bottom right corner of my laptop screen saying that it could not extend the display. I was able to connect the display without issue prior to the update.

I've checked for updates in the Device Manager and everything is up to date.

Other devices can connect via the USB-C adapter.

Potentially related, my brightness settings no longer adjust - the laptop screen stays at the same amount of brightness whether set from 0 all the way to 100.

Windows for home | Windows 11 | Display and graphics
0 comments
Answer accepted by question author
DaveM121 935.7K Reputation points Independent Advisor
2026-06-10T10:26:17.75+00:00

The external monitor problem along with the brightness problem almost certainly indicates there is an issue with the graphics drivers.

The best option is to go to the official support page for your laptop on the Dell website, then from there, manually download and install (not update) the version of graphics drivers they provide.

If you have any difficulty locating that support page, click your Start Button, then just type msinfo and press Enter, please provide a screenshot of the resulting System Information window.

Was this answer helpful?

3 people found this answer helpful.
0 comments

1 additional answer

Sort by: Oldest
Most helpful Newest Oldest

  1. AI answer

    2026-06-10T09:53:39.1233333+00:00

    Follow these steps in order, focusing on what changed after the Windows 11 update:

    1. Confirm Windows is set to extend the display
    • Press Windows logo key + P.
    • Select Extend.
    • If Extend is already selected and nothing appears on the TV, continue with the next steps.
    1. Reseat and test the HDMI path
    • Disconnect all accessories from the PC (other docks, dongles, adapters) to avoid conflicts.
    • Unplug and firmly reconnect:
      • USB‑C adapter to the laptop.
      • HDMI cable to the adapter and to the TV.
    • Try a different HDMI cable.
    • Try a different USB‑C port on the XPS.
    • Test the TV and HDMI cable with another system (which has already been done and works) to confirm the issue is on the laptop side.
    1. Check TV input and HDCP support
    • On the LG TV, make sure the correct HDMI input is selected.
    • If nothing displays, verify that the TV’s HDMI port supports HDCP (per the TV documentation). If it does not, the PC may not send a signal.
    1. Update Windows and drivers
    • Go to Start > Settings > Windows Update > Check for updates and install all available updates.
    • Restart the device after updates.
    • If the problem persists, check for updated video/display drivers from Dell (GPU and USB‑C/Thunderbolt drivers), as driver incompatibility after an update can break external display and brightness control.
    1. Reset graphics and restart
    • Press Windows logo key + Ctrl + Shift + B to reset the graphics driver. The screen may blink and the GPU driver will reload.
    • If that does not help, restart the PC:
      • Start > Power > Restart.
      • If still failing, perform a full shutdown (Start > Power > Shut down) and power it back on.
    1. Test with a single external monitor only
    • Disconnect any other external displays or adapters.
    • Connect only the LG TV via the USB‑C–to‑HDMI adapter.
    • If the TV still is not detected, try another external monitor or TV with the same adapter to see whether the issue is specific to the LG TV or to the laptop’s USB‑C/graphics path.
    1. Consider rolling back the last update
    • If the issue started immediately after a specific Windows update and all steps above fail, use Settings > Windows Update > Update history and uninstall the most recent update that coincides with the problem, then test the external display again.

    Because brightness control and external display both broke after the update, the most likely cause is a display/graphics driver or firmware issue. Ensuring Windows is fully updated, then updating or rolling back display-related drivers (and, if needed, uninstalling the last problematic update) is the key path to restore both external display detection and brightness control.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

    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.