Windows 10: After 20H2 Update one monitor not detected in multi-monitor system.

I have an 8 monitor computer running Windows 10 Pro, four monitors are on one graphics card, two monitors are on another graphics card and two monitors are on the motherboard. It's a relatively new computer, custom built for multi-monitor setup. It was working fine, then I updated to the latest feature update 20H2 and suddenly Windows has stopped recognizing one of the monitors.


If all eight are plugged in one screen will be black and cannot be found by Windows Display Settings, Nvidia graphics drivers GUI or Intel Graphics drivers GUI. If I disconnect a different monitor than the blank one, windows detects the one that was previously blank and puts it in the place of the disconnected monitor. If I then reconnect the monitor cable, the newly plugged in monitor will take over i.e. the originally blank monitor will go blank and show "no signal". If only seven monitors are connected, they will all show up on the device drivers device manager or the Nvida or Intel GUIs, but if an either monitor is plugged in one will drop out.


It's as if the update made it so Windows can only detect seven monitors at a time.


How do I fix this? Will I have to roll back to the previous update?

:)

 

Monitor detection?

Hello,

After the last big update about 3 weeks ago, when I start my system it fails to detect my second monitor. I have checked and secured all the cable connections. It does not matter if the monitor is on or off when I start the system, it is not detected.
When I restart the system, the monitor is successfully detected.

I have also tried to "DETECT" the second monitor when the system did not detect it at startup and it will not detect it.

I have loaded the latest video driver.

Any other ideas at how I can fix this issue?

Thanks!

 

2nd Monitor not detected

I have same problem. Last night windows 10 did what was listed as the winter update. Since then my second monitor just mirrors the first monitor. Everything worked until the update. I have tried several things, booting with just the one monitor (ASUS)
and delecting the first (ACER) and then adding both monitors, the control panel just sees the acer monitor. When I ask to detect second monitor it says second monitor not detected. I tried several different resolutions, that didn't help either. The same
screen appears now on both monitors, but control panel senses only the acer monitor.

 

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.