Windows 10: Primary Monitor Dims When Connecting Second Monitor

I'm currently using an LG 34UC79G-B monitor as my primary display and a Samsung CF390 as my secondary display, running Windows 11.When the LG is utilized as the sole monitor display settings set to "Only Show on 1", the monitor works fine, brightness is great. However, when I switch to "Extend Desktop" to utilize a second monitor, the main monitor dims fairly significantly.Additional information:GPU drivers and Windows are fully updatedAuto-brightness/adaptive brightness is disabledHDR is disabledNo settings are or have been changed, both in Windows and on the monitor's OSDThe monitor works

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Monitor Dims when second monitor is selected

I have 2 monitors (identical View Sonic devices) Recently when I select a program on one of the monitors, the other monitor goes dim. If I select a program on the second monitor, the unselected monitor (first monitor) goes dim. The interesting thing is that if I log in as the administrator both monitors stay bight no matter which one is selected.

Any ideas?

 

Second monitor not detected after update

Hi Tom,

There are several reasons that could have caused the issue you are experiencing. One of these is the update you previously performed in Windows, either it was not configured properly by the system or the update components were corrupted. Kindly answer the
following questions for clarification:

• Have you tried updating the monitor and display drivers?
• Have you tried to use another user profile to check if the issue re-occurs?

Furthermore, we suggest that you add the other monitor manually. This is to ensure that the second monitor is still connected after the update. Here are the steps:

• Type connected devices and open Connected Devices on the
  Windows Search bar.
• Click Add devices.
• Select the Second screen.
• Pick one of the 3 options: Duplicate, Extend, and the Second screen only.
• The Duplicate option will duplicate the primary display to secondary display.
• The Extend option will unite two monitors so you can use them both as one.
• The Second screen only option will, obviously, disable primary and use only the secondary monitor.
• Once you’ve chosen the preferred mode, save changes.

We're looking forward to your response.

 

windows not recognizing second monitor

Hello,

Windows may not recognize another external display device if the display drivers are outdated, or that the monitor is turned off or not plugged in correctly, etc. For us to isolate the issue in connecting a second monitor in Windows 10, kindly respond to
the questions below:

• Have you made any significant changes to your device prior to the issue?
• Did the second monitor work before?
• Have you tried using the monitor to a different computer?
• What happens if you disconnect your primary monitor and connect the second monitor to make it the main monitor?

We look forward to your response.