Hi Jim. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activation, here to help you.
1) Try these fixes for night light on the external monitor:
https://www.majorgeeks.com/content/page/how_to_...
https://helpdeskgeek.com/windows-10/windows-10-...
https://www.partitionwizard.com/partitionmagic/...
https://www.thewindowsclub.com/windows-10-night... (Avoid ad links which intrude into editorial copy, especially avoid Restoro and Reimage ads)
https://www.tenforums.com/general-support/12523...
https://pureinfotech.com/fix-night-light-window...
https://win10faq.com/windows-10-night-light-not...
https://www.youtube.com/watch?v=ga5mBe5uLrw
2) The Display driver is so important here that merely updating it is sometimes not enough. So let's try everything possible to get it working correctly:
First make sure you have updated the Display driver from the PC or Display adapter maker's Support Downloads web page for your exact model number, HP Serial Number or Dell Service Tag - from the sticker on the PC.
While there check also for newer chipset, BIOS/UEFI firmware (very important), network, sound, USB3 and other drivers, comparing to the ones presently installed in Device Manager reached by right clicking the Start Menu.
If necessary first remove the old driver using DDU
https://www.wagnardsoft.com/content/ddu-guide-t... and/or install in Safe Mode with Networking (so you have internet), or Safe Mode, accessed by one of these methods:
https://www.digitalcitizen.life/4-ways-boot-saf.... If new driver still won't install DDU see Lightning Leon's Answer here:
https://answers.microsoft.com/en-us/subject/for...
If this doesn't give you the latest or ideal driver for what you need, compare it to the driver offered by the Intel driver update Utility here:
http://www.intel.com/content/www/us/en/support/...
or the Nvidia Geforce updater here:
https://www.nvidia.com/en-us/geforce/geforce-ex...
or the AMD autodect utility here:
http://support.amd.com/us/gpudownload/windows/P...
For Display issues one fix that is working is to Roll back or Uninstall the Driver on the Display Device > Driver tab, restart PC to reinstall driver.
You can also try older drivers in Device Manager > Display device > Driver tab > Update Driver > Browse > Let Me Pick.
Then you will know you've tried everything in addition to Windows Update drivers.
Adjust the screen resolution until it fits and looks best at Settings > System > Display.
Then watch WIndows Updates which may push a new monitor driver based on the display driver you now have installed.
3) Can you try a more direct connection without an adapter cable? These are often the problem in cases like this.
I hope this helps. Feel free to ask back any questions. Please report back results for all steps given so I know what else to suggest if necessary.
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