How to change desktop background or wallpaper in secure desktop (Winlogon) in windows 10?

Question

How to change desktop background or wallpaper in secure desktop (Winlogon) in windows 10?

Yashwanth Lokam 51

I have tried different ways like SystemParametersInfo and IActiveDesktop to change the background image of secure desktop but nothing worked.

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Answer 1

RLWA32 49,551

As far as I can tell it isn't possible to change the background/wallpaper for the secure desktop (Winlogon).

Even Microsoft's Sysinternals Desktops utility at https://learn.microsoft.com/en-us/sysinternals/downloads/desktops only uses the background/wallpaper from the default desktop when it creates a new desktop object. It also seems that a copy of explorer needs to run with the additional desktop objects. Finally, I observed that attempting to change the background/wallpaper from a non-default desktop doesn't work.

You could try imitating what UAC does -- create a full screen window that displays a color or an image and create your other windows above that in the z-order.

The following image shows my test program's window running on the Winlogon desktop above a full screen window in the z-order. The full screen windows just paints a red background.

And the same concept except using a bitmap for the fullscreen window instead of a solid color background -

Yashwanth Lokam 51 Reputation points

2021-09-07T16:06:06.657+00:00

I am able to create a window but I am unable to run an .exe on top off the window by using CreateProcess method on secure desktop.
RLWA32 49,551 Reputation points

2021-09-07T16:19:53.753+00:00

Did you remember to specify Winlogon as the desktop in the STARTUPINFO structure passed to CreateProcess?

Running notepad on the secure desktop -
Yashwanth Lokam 51 Reputation points

2021-09-08T10:17:03.263+00:00

Do you have any reference code on how to do this?. I am new to creating a window concept.

RLWA32 49,551

This is the code for CreateProcess that started notepad on the secure desktop -

STARTUPINFOW si = { sizeof si };
PROCESS_INFORMATION pi{};

si.lpDesktop = szDesktop;
si.dwFlags = STARTF_USESHOWWINDOW;
si.wShowWindow = SW_SHOW;

if (CreateProcessW(L"C:\\Windows\\System32\\Notepad.exe", nullptr, nullptr, nullptr, FALSE,
    0, nullptr, L"C:\\Windows\\System32", &si, &pi))
{
    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
}

Yashwanth Lokam 51 Reputation points

2021-09-14T17:28:07.683+00:00

I have tried to create a visual studio project for this win32 api window. I have changed the character set to MultiByte character set. But I want to run the project in Unicode character set. When I started the .exe of the win32 api project, I could see a new window appearing but my .exe file is not running. I am getting an application error 0xc0000142. Do you have any idea regarding this?
RLWA32 49,551 Reputation points

2021-09-14T17:41:25.747+00:00

The status code of 0xC0000142 is STATUS_DLL_INIT_FAILED -- "{DLL Initialization Failed} Initialization of the dynamic link library %hs failed. The process is terminating abnormally."

You should ask a new question regarding this latest problem. It would also be helpful if you shared your project on Onedrive (or equivalent service) and posted a link in your new question. That would allow the community to see the code and make it easier to assist you.

Answer 2

Castorix31 90,686

If you're talking about the Lock Screen image that can be changed in Settings (Settings - Personalization)
It can be done with the LockScreen API, like in the SDK sample : Lock screen personalization sample

Answer 3

Yashwanth Lokam 51

Thank you for your response but I am looking to change the background on secure desktop (Winlogon) or any user created desktops not on lock screen.

Castorix31 90,686 Reputation points

2021-09-04T09:26:04.38+00:00

On my OS (Windows 10 1909), the screens are the same : when I logon or when I lock, I have the same background...
RLWA32 49,551 Reputation points

2021-09-04T09:52:29.427+00:00

But if you get a UAC consent prompt for elevation that switches to the secure desktop what do you see?
Castorix31 90,686 Reputation points

2021-09-04T10:06:52.757+00:00

If you mean the Dialog Box called "The consent prompt" at How User Account Control works,
the background is my main desktop (that I change with IDesktopWallpaper)
RLWA32 49,551 Reputation points

2021-09-04T10:34:26.287+00:00

I see the same thing. I think the questioner is asking how to change the secure desktop background/wallpaper to something different from the interactive user's settings (seen on the default desktop). Of course I could be wrong. :)
RLWA32 49,551 Reputation points

2021-09-04T13:52:45.797+00:00

Win32 desktop app running as LocalSystem on the secure desktop (Winlogon) -

If I switch back to the default desktop and start an elevated command prompt then UAC displays an image of the dimmed default desktop for the interactive user with the consent prompt on the secure desktop. When that is dismissed, the secure desktop displays as above.
Yashwanth Lokam 51 Reputation points

2021-09-06T09:01:04.357+00:00

I am getting the same black screen when I run any .exe files programmatically on secure desktop (Winlogon). I need help changing the background image in this scenario. Tried every reference that I could find by I couldn't change the background image.

Answer 4

Tasadduq Burney 8,956 MVP Volunteer Moderator

Hello @Yashwanth Lokam !

Please take the following steps to replace Logon UI logo.

Click Start, type Regedit and press Enter
Navigate to
HKLM\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background
Change value of OEMBackground to 1.
Now navigate to %windir%\system32\oobe, create folder “info”, double click it and create another new folder “backgrounds”
Now place your desired logon file into %windir%\system32\oobe\info\backgrounds
Rename the file to backgroundDefault.jpg. (Please NOTE: Images must be less than 256kb in size).

Hope it helps.

Castorix31 90,686 Reputation points

2021-09-04T10:20:19.857+00:00

This was for Windows 7 (Change the Windows 7 and 10 Logon screen backgrounds)

Answer 5

Artemiy Moroz 271

hi there!

If you are to create a separate desktop and then create a window with a background on it, maybe you could find some use of my code. This sample code creates a separate desktop and then creates a window on it. The sample is written with MFC in mind, but it can be rewritten to pure WinAPI if needed.

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How to change desktop background or wallpaper in secure desktop (Winlogon) in windows 10?

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