How to get game build to run on Main Display

Technically things seem to work correctly I suppose, canvas/cameras are targeting Display 1, but on my computer that is not my Main Display in Windows, display 2 is.

Every other game on the planet opens on my Main Display, and all builds I've ever made in Unity also opened on my Main Display until I upgraded to Unity v2021.

Now all builds open on my secondary monitor, which is not my Main Display, but does show as Display 1 in Windows display settings.

I can change this via shortcuts and can include video settings for players to change it, but is there anyway to have the build work like it did before, or tell unity builds to open on the Main Display regardless of what the display number is?

 

Today I installed Unity v2021.3.1f1 LTS (cause I wanted to get my project into LTS) and upgraded my older v2020.x LTS project, tested a build once I got through all the upgrade issues and saw the wrong monitor problem.

I have also created multiple builds of test projects with v2021.3.1f1 LTS and see the same problem.

I have just done a new test, new empty project with no changes/other imports, made a Windows 64bit build of the default empty scene and same problem.

Once I shift the EXE to another monitor (using WinKey+SHIFT+ArrowKey) the EXE will then open on the Main Display. Nothing I did in code of course, just Windows 10 doing its thing.

 

Will do, but it does beg the question: How do you tell Unity to use the Main Display instead of whatever is on Display 1?

What if I actually want my game to start on Display 1 even when it isn't the Main Display?

I don't see any settings related to this (use Main Display), only the list of Displays for things like Canvas and Cameras.

 

Side note, when making a new unity project, Unity itself opens on my Display 1, not my Main Display.

What exactly did you want from GetDisplayLayout()?

That just gives me a list of my displays in order from Display1, Display2 etc.

 

Well it's giving my displays back in the order Display1, Display2, which I suppose makes sense.

But in my case, Display2 is my Main Display. Are you expecting the order should come back Display2, Display1?

My log info output in order:

Display1
Name: W2340
Height: 1080
Width: 1920
RefreshRate: 148351648/148351648
WorkArea: (x:0, y:0, width:1920, height:1040)

Display2 (Main Display)
Name: B326HUL
Height: 1440
Width: 2560
RefreshRate: 59951/59951
WorkArea: (x:0, y:0, width:2560, height:1400)

 

Bug reported, ticket number: 1423262
Case: 1180011

 

FYI, bug was accepted and can be reproduced, new link to monitor progress: https://issuetracker.unity3d.com/is...he-wrong-display-when-main-display-is-changed

 

This bug affects my project too, and it's quite a critical issue in my case. Is there a workaround to this until it's fixed in the 2021 LTS?

 

Hey @Tautvydas-Zilys, sorry for nagging, but do know if this issue is still being worked on?
It's been set as "Fix In Review for 2022.2.X" for quite a while now, and I'm starting to fear it will be another couple of months before this fix is backported into the 2021 LTS.

 

Thank you for letting me know it's being worked on. I can relax now that I know it's not in limbo.

 

Just recently migrated from a 2020 build up to 2021.3.4f1 and had this problem as well. Thanks to this sample https://programtalk.com/vs4/csharp/...owSample/Assets/Scripts/SettingsMenuScript.cs I fixed this using the following code on a script that runs on my splash screen Scene.

Code (CSharp):

1.    
2.     void Awake()
3.     {
4. #if !UNITY_EDITOR
5.         // fixes new Unity2021 bug where the secondary monitor was being chosen when the game launches in a release build
6.         StartCoroutine("MoveToPrimaryDisplay");
7. #endif
8.     }
9.  
10.     IEnumerable MoveToPrimaryDisplay()
11.     {
12.         List<DisplayInfo> displays = new List<DisplayInfo>();
13.         Screen.GetDisplayLayout(displays);
14.         if (displays?.Count > 0)
15.         {
16.             var moveOperation = Screen.MoveMainWindowTo(displays[0], new Vector2Int(displays[0].width / 2, displays[0].height / 2));
17.             yield return moveOperation;
18.         }
19.     }

 

I deleted the registry keys. Using Build & Run opens it on my main monitor. Opening directly from a Windows Explorer opens it on the screen that contains the window.

I don't usually open my builds on the secondary monitor, so it's weird it was set as the select monitor when I ran it for the first time after upgrading to 2021.3

 

I encountered this as well.
Builds made with 2021.3.4f1 opens on second monitor, while builds made on 2021.1.19f1 opens on main monitor.
If I change the 2021.3.4f1 build to open on main monitor (ALT+ENTER and move it to correct monitor), all builds made on 2021.1.19f1 will now open on second monitor instead, completely opposite of 2021.3.4f1.

 

I got an email saying this is now fixed, but in version 2023.1x.

No indication yet of backporting to 2021 LTS although I will try updating to 2021.3.6f1 LTS in the hopes it is fixed there too.

Note that 2023.1.x isn't available even as a preview alpha/beta release yet.

 

Just updated to Unity 2021.3.5 and I'm encountering this problem too.

 

same problem here

 

Thank you very much for fixing this and letting us know about it.

 

So I just upgraded to 2021.3.15f1 and now the following workaround I've been using in 2021.3.4f1 is broken:

Code (CSharp):

1.    
2.     void Awake()
3.     {
4. #if !UNITY_EDITOR
5.         // fixes new Unity2021 bug where the secondary monitor was being chosen when the game launches in a release build
6.         StartCoroutine("MoveToPrimaryDisplay");
7. #endif
8. }
9.  
10. IEnumerable MoveToPrimaryDisplay()
11.     {
12.         List<DisplayInfo> displays = new List<DisplayInfo>();
13.         Screen.GetDisplayLayout(displays);
14.         if (displays?.Count > 1) // don't bother running if only one display exists...
15.         {
16.             var moveOperation = Screen.MoveMainWindowTo(displays[0], new Vector2Int(displays[0].width / 2, displays[0].height / 2));
17.             yield return moveOperation;
18.         }
19.     }

I have 3 monitors on my windows 10 pro machine, the one in the center with "make this my main display" checked has an Identity of 1. As of Upgrading to 2021.3.15f1 my builds are appearing on my left monitor which has an identity of 2 and has "make this my main display" un-checked.

Per your statement "Primary display is now always the first display we return from Screen.GetDisplayLayout() API.", I'm seeing that does not appear to be the case, given my code above, the value of displays[0] is neither the first monitor based on Identity nor is it the monitor configured with "make this my main display" checked.

The good news is that after commenting out my workaround code and doing another build, manually moving the window using WIN + SHIFT + arrow keys did in fact work and then upon restarting the game it launched in the primary display as expected.

 

Yup, here ya go. Please let me know if you need something further.

 

Hi @toddw, it seems that the issue is with the StartCoroutine which isn't executed anymore. Calling directly MoveToPrimaryDisplay as a void function works for me.

 

Interesting, just tested this and I'm seeing the same thing, the MoveToPrimaryDisplay method won't fire if called via StartCoroutine in the scope of Awake. Not sure if that is a new bug or a new fix in Unity's functionality. Either way I'm no longer calling the method anyway, but that is an interesting find, thanks fabrmooc.

 

Sure.



In light of @fabrmooc's post I'm guessing my issue was the fact that the IEnumerable method when called via StartCoroutine in the scope of Awake is no longer executing in Unity 2021.3.15f1, which would explain why my solution suddenly stopped working as my first monitor in the array looks accurate. I suppose I should have used the Watch or Immediate window to verify the contents of displays[0] was indeed a display other than my primary, but I must have just assumed it wasn't given the behavior of the build, sorry about that, I should have been more thorough.

 

Hi!

Some players of my game reported the same thing, that the game starts on their second monitor and it keeps starting there every time they open up the game.
I can't reproduce the problem because I only have 1 monitor.

I use Unity 2019.4.40f1 LTS

 

Any progress on this?

 

So, I should just tell them to use WIN + SHIFT + LEFT/RIGHT ARROW to move the game between different monitors?
Or is there a script or something that I can use to make it more consumer friendly?
Thank you for the reply!

 

This code works perfectly:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using System.Threading.Tasks;
5.  
6. public class Display : MonoBehaviour
7. {
8.     async Task MoveWindowTask (int index) // Minimum Unity Version required: 2021.2
9.     {
10.         List<DisplayInfo> displayLayout = new List<DisplayInfo>();
11.         Screen.GetDisplayLayout(displayLayout);
12.         if (index < displayLayout.Count)
13.         {
14.             DisplayInfo display = displayLayout[index];
15.             Vector2Int position = new Vector2Int(0, 0);
16.             if (Screen.fullScreenMode != FullScreenMode.Windowed)
17.             {
18.                 position.x += display.width / 2;
19.                 position.y += display.height / 2;
20.             }
21.             AsyncOperation asyncOperation = Screen.MoveMainWindowTo(display, position);
22.             while (asyncOperation.progress < 1f)
23.             {
24.                 await Task.Yield();
25.             }
26.         }
27.         else
28.         {
29.             await Task.CompletedTask;
30.         }
31.     }
32.  
33.     async void MoveWindowAsync (int index)
34.     {
35.         await MoveWindowTask (index);
36.     }
37.  
38.     void Update()
39.     {
40.         for (KeyCode keyCode = KeyCode.Keypad0; keyCode <= KeyCode.Keypad9; keyCode++)
41.         {
42.             if (Input.GetKeyDown(keyCode))
43.             {
44.                 string key = keyCode.ToString();
45.                 int index = System.Convert.ToInt32(key[key.Length-1].ToString());
46.                 MoveWindowAsync(index);
47.                 break;
48.             }
49.         }
50.     }
51. }

For main display call MoveWindowAsync(0);