Device id problem of displays

Question

Two different displays and not just one. It is Acer and Samsung displays but shows as one. Device Manage don't see them property.

Answer 1

Hi David Anthony Black,

From your description, it sounds like Windows may be using cached monitor information or is not correctly detecting the unique display identifiers (EDID) for each monitor. This can sometimes happen after display hardware changes, driver updates, or when using adapters, docks, or other intermediary devices.

Here are some additional steps that may help:

1. Open Device Manager > View > Show hidden devices.
2. Expand Monitors and uninstall all monitor entries, including any greyed-out devices.
3. Restart the PC and allow Windows to detect the displays again.

If you're using a dock, KVM switch, hub, or video adapter, temporarily connect the monitors directly to the computer (if possible) and check whether they are identified correctly. Please verify whether both displays appear separately under Settings > System > Display and Device Manager > Monitors after reconnection.

If the issue continues, please share how the monitors are connected (directly, via dock, adapter, KVM, etc.) and what appears under Device Manager > Monitors. That information can help narrow down whether the behavior is related to display detection, graphics drivers, or the connection hardware.

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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Answer 2

If two physical monitors are being treated as one display, first check whether they are connected to separate video outputs or through a splitter. A splitter can cause both screens to mirror as a single display instead of appearing as separate monitors.

If the monitors are connected separately, use this Windows troubleshooting path:

1. Open Display settings and select Detect to force Windows to look for the missing monitor.
2. Select Identify to see how Windows is numbering the screens.
3. In the display layout, make sure each screen is set to Extend desktop to this display rather than duplicate.
4. Open Device Manager and expand Display adapters to confirm the graphics adapter is present.
5. If the issue started after an update, roll back the display driver:
   • Search for Device Manager
   • Expand Display adapters
   • Right-click the display adapter > Properties > Driver tab > Roll Back Driver
6. If rollback is not available, reinstall the display driver:
   • In Device Manager, expand Display adapters
   • Right-click the adapter > Uninstall device
   • If shown, select Attempt to remove the driver for this device
   • Restart if prompted
   • Open Device Manager again
   • Right-click the adapter > Update driver > Search automatically for updated driver software

If one old or incorrect monitor identity is stuck in Windows, uninstall the monitor entry under Monitors, restart the PC, and then install available driver updates from Windows Update including Optional Updates.

If this is a laptop, another possible cause is hardware display limits. Some laptop graphics adapters support only two displays at one time. In that case, Windows can fail to save a three-display configuration, and one screen may not appear separately.

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References:

• Troubleshoot external monitor connections in Windows
• monitor device not updated when monitor replaced with different one - Microsoft Q&A
• Why is Windows not recognizing a second monitor? - Microsoft Q&A
• Error message when you configure the display settings to try to use three or more displays on a laptop that is running Windows 7 and Windows 8: "Unable to save display settings"