Windows 10 multiple display - windows are moved and resized on display power cycle

Hello,

I think I may have a solution for this problem.  It appears Windows 10 keeps a history of all the monitors it encounters during its life time.  This includes the basic monitor support during the OS install.  So, if you enable "Show hidden devices" in the Device Manager you will see all the monitors that were connected to your system.

Start the Control Panel as Administrator:

1.  Start Control Panel --> Device Manager
2.  Select View --> Show hidden devices
3.  Expand Computer --> Monitors

When you expand the Monitors you will see your current monitor (highlighted) and all the disconnected monitors (greyed out).   You may see monitors with "non-PNP" and "PNP" listed as well.  I believe these are aliases to your current monitor (at a lower resolution) before Windows installed drivers for it.   

I uninstalled ALL the greyed out monitors.  Right-click on these monitors and select uninstall.  Keep only the highlighted monitor you are currently using.  

4.  Uninstall all greyed out monitors (even non-PNP and PNP monitors)
5.  Reboot your system.

After doing this my windows don't resize after my monitor goes to sleep.  You can quickly test this by temporarily setting your monitor sleep time to 1 minute.

Settings --> System --> Power & Sleep --> Screen [1 minute]

Cheers,

Stephen

I can see the hidden devices, and I can delete them. But they all come right back, so this is not a solution.

Because the problem of windows rearranging happens on my Intel NUC but not my HP tower, both running 1803, I believe it is probably a problem with the manufacturer-provided display driver rather than Windows. Or both; it is probably a Windows design flaw that it allows this to happen.

Actually nope - this doesn't fix it at all. It's a joke that in 2018 this still happens - I have 3 4K monitors - anytime they go dark I have to manually drag 20 windows to the right location - huge productivity hit.

 I agree and have the same problem with my setup (A 4K monitor, a 1440p monitor and a 1200p monitor).  The problem has nothing to do with registry entries, it's due to the longer amount of time the 4K monitor takes to wake from sleep vs the other 2.  Windows 10 isn't allowing the 4K monitor enough time to resume before assuming it's not present and moving all the other windows to the other 2 monitors.  It's actually discouraging me from locking my PC as I don't want the hassle of manually rearranging the windows when I return.  Ridiculous.

Ok, the following seems to have worked for my Intel NUC connected to an LG 43UD79 4K monitor. Now when I switch inputs on the monitor with my other computer (an HP tower) and then switch back, or if the monitor goes to sleep and is woken up, the windows stay put. The fix works without rebooting, and it persists across reboot.

Under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration there are two entries:

1. GSMxxxxx representing the LG which has PrimSurfSize.cx 3840, PrimSurtSize.cy 2160, Stride 15360.

2. NOEDIDxxxxx representing some other kind of (default?) monitor which has 1024, 768, 4096, respectively.

   (there is no SIMULATEDxxxxx in my case)

The fix was to change all the relevant values in NOEDID to match GSM. In my case (again this is a 4K monitor), I changed them as follows:

NOEDIDxxxxx\00\PrimSurfSize.cx = 0x00000f00 (3840)

NOEDIDxxxxx\00\PrimSurfSize.cy = 0x00000870 (2160)

NOEDIDxxxxx\00\Stride = 0x00003c00 (15360)

NOEDIDxxxxx\00\00\ActiveSize.cx = 0x00000f00 (3840)
NOEDIDxxxxx\00\00\ActiveSize.cy = 0x00000870 (2160)
NOEDIDxxxxx\00\00\DwmClipBox.bottom = 0x00000870 (2160)
NOEDIDxxxxx\00\00\DwmClipBox.left = 0x00000000 (0)
NOEDIDxxxxx\00\00\DwmClipBox.right = 0x00000f00 (3840)
NOEDIDxxxxx\00\00\DwmClipBox.top = 0x000000000 (0)
NOEDIDxxxxx\00\00\PrimSurfSize.cx = 0x00000f00 (3840)
NOEDIDxxxxx\00\00\PrimSurfSize.cy = 0x00000870 (2160)
NOEDIDxxxxx\00\00\Stride = 0x00003c00 (15360)

I've also been having this issue since I bought a new monitor this week.  I'm running Windows 10 (1803) with an AMD Radeon RX580.  My previous monitor is about 9 years old, it was a 24" Samsung monitor.  The new one I picked up is an LG 28" monitor.  I've set them up as dual displays, with the old 24" connected via HDMI as the secondary screen, and the LG 28" connected via DisplayPort as the main screen.

Even without Windows going to sleep or screensaver, I manually turn both monitors off.  As soon as I turn them a few seconds after, the windows on my main screen re-sized (shrunk).  Someone earlier suggested that this may be related to power and detection by Windows for the DisplayPort, and I'm thinking along those lines too.  In fact, everytime when I turn the main monitor on (the one that's on DisplayPort), it will take a several seconds for the screen to load up.  Even worst, on occasion, when I've tried to turn the main monitor on, it takes too long to receive a signal from Windows, and my monitor displays an error saying that there is "no signal, connect a device, etc.".

So to the fellow that suggested not using DisplayPorts if you're doing dual displays, I think you're right, but that is quite unfortunate as my system is brand new and only offers one HDMI slot (and 4 DisplayPorts).

I really hope an update will fix this in the short future.  As many have said, dual displays is such a common thing nowadays.

I was about to give up but did one more search which turned up a solution seems to have worked (at least for my case).    This link:

http://www.tenforums.com/general-discussion/11890-intel-nuc-windows-resized-after-waking-sleep.html

points to a solution (option 2) which is here

http://www.tenforums.com/tutorials/5990-dpi-scaling-level-displays-change-windows-10-a.html#option2

Starting with 1703, Option 2 is no longer available.  You need to use Option 3, linked here:

https://www.tenforums.com/tutorials/5990-change-dpi-scaling-level-displays-windows-10-a.html#option2

This worked for with with a Surface Book 2, and two Dell P2715Q externals hooked in to a Surface Dock, with custom scale factor set to 150.