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Environment: Windows 10 Pro 20H2 x64 running on MacBook Pro 2019 (bare metal), with an LG 4k monitor, each connected to a CalDigit T3 Plus dock. MBP graphics card is AMD Radeon Pro Vega 16. AMD drivers are current.

Whenever the screens go to sleep, after waking, all application windows are moved to the laptop screen. I have to manually reposition the windows which were on the Asus monitor. I don't have this problem when running macOS. Very frustrating, of course - any assistance is appreciated.

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  • How are the monitors connected and to what?
    – harrymc
    Apr 8 '21 at 19:01
  • @harrymc MBP and the LG monitor are both connected to the CalDigit dock.
    – Conrad
    Apr 8 '21 at 19:04
  • I mean connected via which type of cables.
    – harrymc
    Apr 8 '21 at 19:06
  • @harrymc Thunderbolt 3 cable from the Mac to the CalDigit dock; DisplayPort from dock to monitor.
    – Conrad
    Apr 8 '21 at 19:08
  • MS is apparently going to fix this in Windows 10 - no scheduled release date as of yet: pcworld.com/article/3616968/…
    – Conrad
    May 4 '21 at 16:40
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DisplayPort ports under Windows are implemented differently than VGA and DVI ports, in that when they enter the sleep state Windows treats them as if they were removed, even displacing their displayed windows to other monitors. When the monitor wakes up, Windows treats it as a new device being discovered. This behavior might be the cause of your problems.

One solution might be to disable the monitors from sleeping:

  • Open Control Panel / Power Options
  • For your power plan click on Change plan settings
  • Change the Turn off display drop-down box to Never
  • Click on Save changes

Another solution which will prevent Windows from verifying the continued presence of the DisplayPort monitors and so to not detect that they are in sleep, is to keep the EDID properties of the DisplayPort monitors.

For this solution see these answers of mine (you are not the only one to have had this problem):

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It was indeed related to the EDID. In the AMD Radeon Pro Settings software (GUI for the AMD display driver), under Display -> EDID Emulation, I clicked Emulate All Displays, and that apparently froze the EDID for the external monitor. Now when the screens wake, all windows remain in their proper place.

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  • I might have spoken too soon - now the cursor is an amorphous rectangle when it is over the LG monitor - will have to investigate more...
    – Conrad
    Apr 9 '21 at 18:16

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