Hi roger plant,
Since the issue started immediately after a recent Windows update and the monitor was previously working, the problem may be related to how the display hardware is being detected or how the graphics driver is interacting with the external monitor.
You can try the following quick checks:
1, Reset the graphics driver
- Press Windows + Ctrl + Shift + B.
- Wait a few seconds and check whether the monitor is detected.
2, Refresh monitor detection
- Open Device Manager > Monitors.
- Select View > Show hidden devices.
- Remove any greyed-out monitor entries, then restart the PC.
3, Try a different graphics driver version
- In Device Manager > Display adapters, open your graphics adapter properties.
- If available, use Roll Back Driver to test whether an earlier driver restores monitor detection.
4, Install the latest driver from the PC manufacturer - download and install the display/graphics driver specifically provided for your laptop model rather than relying solely on the driver currently installed.
If the monitor is still not detected after these steps, please share more information as suggested by the Independent Advisor that can help narrow down the cause and identify the most appropriate next step.
Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.
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