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I just updated to Windows 10 and discovered that Microsoft broke this method of adding a fake second monitor: Is there a way to fake a dual (second) monitor which I rely on for scaling some small programs to full screen with OBS. The "Detect" button in Control Panel seems to do nothing, and the "Detect" button in Settings simply says a display was not connected.

Is there any way to force Windows 10 to think there's a display connected on VGA without extra hardware or paid software? I'm using a laptop with an NVIDIA 970M with HDMI, VGA, and DisplayPort out.

What I've tried:

  • The "My display is not shown..." option in the NVIDIA Control Panel, which won't let me add anything and only has options for televisions
  • SpaceDesk, which almost works except that my real display is bumped to #2, and requires a client to be connected
  • DemoForge Mirage/ZoneScreen, which also require a connected client and are somewhat unstable on recent versions of Windows
  • VirtualMonitor which I think is almost what I want, but isn't compatible with Windows >7 and has some compatibility issues (?)

Note that I am not looking for Virtual Desktop software, and I don't need anything as fancy as Matrox PowerDesk or Virtual Display Manager.

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    What's OBS stand for? and which specific method did you use?
    – Journeyman Geek
    Commented Jul 30, 2015 at 4:10
  • 1
    Open Broadcaster Software. It's mostly used for streaming, but I use the fullscreen preview mode on my real screen which scales the low resolution program on the fake second screen to full screen. I control the second program by just moving my mouse over to the fake monitor. And could you clarify what you mean by "which specific method did you use?"
    – xperia64
    Commented Jul 30, 2015 at 16:54
  • Ugly,buyt possibly of interest: superuser.com/questions/1271344/…
    – Hennes
    Commented Mar 1, 2018 at 19:59
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    I was able to get this to work by just connecting one end of a VGA cable to a VGA-to-Display Port adapter and the other end of it to my Win 10 computer. Weird but it works. If you remove the adapter, it stops working. Bear in mind, the cable is connected via a dock though, so I don’t know if direct connection would work (probably would). Don’t know if HDMI would work (probably won’t). Commented Jun 11, 2018 at 17:53

8 Answers 8

17

This is by far not the ideal solution, but for now it will do: I put a 102 Ohm resistor across pins 2 and 7 of my VGA port (also known as the headless Mac Mini trick), and Windows 10 now believes I have a second monitor attached.

On a different computer I had to use pins 1 and 6 and reboot before the "monitor" would work.

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    For anyone who doesn't fancy sticking resistors anywhere, there are also commercial products, just search for "fake monitor dongle".
    – chris
    Commented Mar 23, 2020 at 9:22
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    what resolution does windows detect for this fake monitor? Commented Jul 19, 2020 at 9:10
  • that's fantastic Commented Jan 5, 2022 at 13:23
  • Likely anything up to the physical limits of the interface is supported if you set a custom resolution. On the other hand, putting aside VGA is kinda on a downturn, I'm wondering if Displayport's Multi-Stream Transport couldn't be used to have nearly infinite displays with just a single dummy plug.
    – mirh
    Commented Sep 17, 2022 at 0:39
13

Just spent last two hours trying to figure this out.

  1. First go to Control Panel (not Settings app)
  2. Go to Adjust Screen Resolution. You will get a similar window as you did in Windows 7.
  3. Click Detect
  4. Go to display Drop Down and select "Display Device on VGA"
  5. Select Desired Resolution. If windows is unable to save your settings use the software from your video card to adjust the resolution.
  6. If you aren't able to output the display to the Fake screen only, Press Windows+P and the select "Second display only"

I hope this helps.

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    thanks! I did not know the control panel still existed. Still the virtual display is not detected though.
    – user643011
    Commented Oct 17, 2015 at 16:39
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    It seems the "Adjust Screen Resolution" was removed and no longer exists in Windows 10 in 2017. Commented Apr 7, 2017 at 13:06
  • 6
    I can confirm that "Adjust Screen Resolution" does not exist any more :-( Commented May 3, 2017 at 13:14
  • 1
    Just had to deal with windows again after years and 50% of my time is finding patches/workarounds Commented Dec 28, 2017 at 8:54
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    @MarkusvonBroady Is there another solution for new versions of Windows 10?
    – Ebram
    Commented Jul 17, 2019 at 23:54
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I found this forum post which provides a link to a pre-built driver which adds up to 4 virtual displays. As far as I understand, it's a free part of a paid software named Amyuni USB Mobile Monitor (as in "free beer", but there may be other license restrictions).

So:

  1. Download and unpack https://www.amyuni.com/downloads/usbmmidd_v2.zip somewhere, preferably without spaces or non-Latin characters. Its SHA256 was 629b51e9944762bae73948171c65d09a79595cf4c771a82ebc003fbba5b24f51 for me, and VirusTotal sees nothing immediately wrong.
  2. Start command line in the directory you've just unpacked.
  3. Run deviceinstaller64 install usbmmIdd.inf usbmmidd (on 32-bit systems use deviceinstaller instead) as an Administrator to install the driver.
  4. Run deviceinstaller64 enableidd 1 to enable an additional display. It's 1920x1080 by default, but other resolutions can be configured in the driver.

They even provide additional instructions in a idd_instructions.txt file inside as well as uninstall commands.

There is also a Windows 10 Only! warning, so it may not work on Windows 11.

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  • This solution works perfectly on my machine with Windows 11 22H2. The OP in the original post said it is for Windows 10 and higher, so I think it might also work well with future versions. Commented Nov 25, 2022 at 0:51
  • This was a great, simple solution. I am using this to avoid Windows rearranging my windows when using a KVM switch.
    – alvinbaena
    Commented Mar 7, 2023 at 21:34
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I had the same problem and came up with a fairly simple solution: Just connect your primary screen twice. Most displays have 2 inputs and you just need another display cable to connect it.

A fake software driver wouldve been more elegant and less power consuming but this works fine too :)

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    This would work, but I am using a laptop.
    – xperia64
    Commented Oct 4, 2015 at 16:52
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VirtualMonitor relied on mirror drivers to work, and that's why it died once Windows 8 removed XPDM support.

On newer Windows instead, in order to manipulate displays you must use (duh) WDDM. And this used to require untold hardships, between having to emulate some quirks of "real" hardware (funnily enough, even headless systems and so-called Display Only Drivers need certain predispositions) and reinventing the entire wheel of a graphics driver too.

Or you also reportedly had the crazy option of hooking the system WDDM interfaces themselves.. which on the one hand is a way smaller endeavour, but on the other it does in turn require even more specialized skills to disassemble and step through the totally undocumented kernel internals (let alone any potential OS/GPU version idiosyncrasy).

By all means, it was all eventually possible with very specialized drivers but you could argue in a sense that the simplest solution for a long time was really just spoofing your graphics card with the VGA trick or one of those physical fake monitor dongles (whose EDID could be then further customized as much as you want with CRU). Quadro might even have the feature built-in btw.

But this thankfully changed with W10 1607 (and WDDM 2.1 presumably?) and the introduction of Indirect Display Drivers. So TL;DR you can use IddSampleDriver and call it a day (instructions). End. EDIT: note that certain features (such as HDR or realtime GPU prioritization) are only available in W11, so you may still be out of luck otherwise with this shortcut.

Shoutout to the Spacedesk developer for much of the info I used here.

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  • Thanks for this. TL;DR is download this repo, copy and paste into C:/, They now include instructions for this application in the README inside the subdirectory (not the one in the root directory).
    – BenB
    Commented Dec 1, 2023 at 2:07
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The so-called "elegant" software solution:

Apparently, custom resolutions can be set up in the registry somehow. Instead of messing with it, I used CRU, (Custom Resolution Utility), a free software package did the trick.

After messing around with the standalone program for a few minutes, it did what I wanted. Then I messed it up, played with it some more without reading the instructions and it worked even better.

I needed a dual monitor solution for SplashTop without an extra monitor. I also needed to boost the resolution from 900p to 1080p.

I temporarily plugged into the second monitor port, then used CRU. Then I realized how bad SplashTop's dual monitor support is, and wanted to go back to one.

So unplug the second monitor connection, right? Nope. The second virtual monitor persisted anyway. So I deleted it in CRU, which Windows respected. CRU had it wrapped around its finger.

The remote host chugs along at a decent little 900p, which looks tiny and/or fuzzy on my bigger screen.

Thanks to CRU, I'm logged in at 1080p on my local end. Which means no sitting next to the noisy graphics card and air cooling.

Still no dual monitor capability for my GPU-accelerated remote desktop, so I'll probably need a second piece of software (remote desktop/logmein) just to transmit the second virtual monitor CRU gives me. Haven't figured out that part yet.

Privacy concerns aside, Windows 10 Enterprise with its Remote Desktop FX seems to have that figured out. Performance looks pretty darn good, too.

You could call that elegant if you want.


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  • CRU doesn't support faking monitors, so this seems just a convoluted way to say "find anything else to attach to your system display outputs".
    – mirh
    Commented Sep 17, 2022 at 0:32
2

xperia64's answer notes that putting a resistor between 2 of the VGA pins works, but the pins can differ from machine-to-machine.

From the VGA pinout, it can be seen that connecting 1 & 6 connects red to red-ground, and 2 & 7 connects green to green-ground. On my system, it was required to connect 3 & 8 (blue to blue-ground) to get this to work.

So, it seems like an all-encompassing solution would be to connect resistors between pins 1 & 6, 2 & 7 and 3 & 8.

The resistances don't seem to matter too much. The spec says 75 ohm, but anything in that ballpark seems to work. (Too low could risk damage, too high it might not detect.)

0

On Windows 10 second display can be added by pressing Win+P and selecting needed option in the appeared panel at the right side of the desktop.

See screenshot

I have only one real display, but I can add another one using Win+P.

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    This is for a real screen, the question is to fake one
    – Ohad Cohen
    Commented Dec 31, 2017 at 15:05
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    @OhadCohen It doesn't matter. I have only one real display, but I can add another one using Win+P Commented Jan 3, 2018 at 11:51
  • This works on some machines. But not all of them.
    – Ebram
    Commented Jul 17, 2019 at 23:40
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    This will not work if you already have 2 displays but you want to add a third one. Commented May 11, 2020 at 11:37
  • This worked for me, but it did not remember it after rebooting. Is there any way to make it remember it after rebooting? Commented Apr 8, 2021 at 6:42

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