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I'm using Windows 10 connected to a computer monitor with DisplayPort and a Samsung TV with HDMI. I have the monitor as the second screen (id=2) and the TV as the first one (id=1).

Most of the time I only want to use the monitor and I do that by switching the TV off and doing Windows+P so it's set to "Second Screen Only".

The problem is that the TV is detected most of the time, but sometimes the detection gets lost for a second and all my windows are rearranged (even though my monitor is the only thing on). So it's basically a useless rearrangement. This all looks like my screen goes off for a second and goes back on every 2/3 minutes while the TV is off.

I have tried deactivating the TV, checking sleep options, try to reorder display output ids (but was not able to)... Is there any solution for this?

What it looks like: https://www.youtube.com/shorts/Hq-GeVZ39c8

jmriego
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DisplayPort acts as a PNP device, so turning off the monitor, even for an instant, is treated as if it was removed and windows are moved out and rearranged because Windows forgets this device, until it is turned on again and is "discovered".

A solution which will prevent Windows from verifying the continued presence of a DisplayPort monitor and so to not detect that it's off, is to keep the Extended Display Identification Data (EDID) properties of the monitor.

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

harrymc
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  • sorry, but I think the issue is on the HDMI port actually. If I physically disconnect the HDMI cable that goes to the TV, I can use the monitor (which is DP) with no issues. I'm still trying to understand if there's still something related in your answer so sorry if I'm missing something – jmriego Sep 13 '22 at 19:31
  • I seem to have switched them around. The EDID solution might also apply to HDMI, but why do you define the TV as primary monitor? – harrymc Sep 13 '22 at 19:36
  • mostly because when I switch on the TV I'm planning on using it for gaming so I want games to open on the TV by default. But I'm happy to do any workarounds needed – jmriego Sep 13 '22 at 19:50
  • Try to make the computer monitor the primary. For the games, see [How to force applications to open on primary monitor in Windows 11/10](https://www.thewindowsclub.com/how-to-force-applications-to-open-on-primary-monitor-in-windows-10). – harrymc Sep 13 '22 at 19:54
  • thanks @harrymc! I just tried that but sadly the DP monitor keeps on randomly going black and windows rearranging any time the TV is connected – jmriego Sep 13 '22 at 20:08
  • The EDID solution should cause Windows not to test at all if the monitor is connected. You could also check if there is a driver update for the display driver on the manufacturer's website. Ditto for the computer monitor (monitors may sometimes also have drivers). – harrymc Sep 13 '22 at 20:13
  • no luck I'm afraid. I think other issues seem to talk about the display switching off but still connected, I have an issue that Windows does not detect a display at all. As if the cable was disconnected. I uploaded a video to be clear what I mean – jmriego Sep 16 '22 at 14:42
  • Are you sure there are no hardware problems? – harrymc Sep 16 '22 at 14:47
  • I'm not aware of any issues as if the TV is on, it works constantly with no issues. The only thing I'm a bit suspicious of is that I'm using a very long HDMI cable (15 meters fiber cable) but as the display works I'm not sure it might have an issue with sleep mode or something – jmriego Sep 16 '22 at 17:16
  • 15 meters is just about the maximum distance for fiber and requires the highest-quality cable. See [Maximum HDMI Cable Length: How to Extend Further?](https://nerdtechy.com/maximum-hdmi-cable-length) – harrymc Sep 16 '22 at 18:58