Customize Windows 10+ default theme

Published on: Sep 13, 2022 - Last update: Sep 14, 2022

Url: https://nosari20.github.io/posts/windows-default-theme/

Content

Purpose
Study
PowerShell script
Sources / usefull resources

Purpose

One day, I wanted to change the default wallpaper and lockscreen of Windows compters for all the user profiles and let the users change these settings as they want. I find different ways by browsing Internet but they did not answere all my needs. My needs were the folowing:

Set custom wallpaper
Customize wallpaper screen
Set lockscreen
Allow users to change lockscreen
Apply this to existing and/or new profiles

Study

C# code integration (wallpaper)

Technical basis

This solution relies on the Win32 API function SystemParametersInfo from user32.dll. This script must be executed in User context or ran using ServiceUI.exe from Microsoft Deployment Toolkit

Limitations

Must be executed in user context
Apply only on current user

Code snippet

# Define wallpaper function
function Set-Wallpaper($MyWallpaper){
    # Define C# code as string
    $code = @' 
    using System.Runtime.InteropServices; 
    namespace Win32{ 
        
        public class Wallpaper{ 
            [DllImport("user32.dll", CharSet=CharSet.Auto)] 
            static extern int SystemParametersInfo (int uAction , int uParam , string lpvParam , int fuWinIni) ; 
                
            public static void SetWallpaper(string thePath){ 
                SystemParametersInfo(20,0,thePath,3); 
            }
        }
    } 
'@
    # Import C# class
    Add-Type $code 

    # Call C# function
    [Win32.Wallpaper]::SetWallpaper($MyWallpaper)
}

## Call your function
Set-WallPaper("C:\Wallpapers\nature.jpg")

Registry keys (lockscreen)

Technical basis

We can use the following registry value to customize lockscreen:

Name: LockScreenImage

Path: HKLM:\SOFTWARE\Policies\Microsoft\Windows\Personalization\LockScreenImage

Type: String

Value: <path to lockscreen image>

Limitations

No limitation found yet

Code snippet

$regKey = 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\Personalization'
# Create the key if it doesn't already exist
if (!(Test-Path -Path $regKey)) {
   $null = New-Item -Path $regKey
}

# Now set the registry entry
Set-ItemProperty -Path $regKey -Force -Name LockScreenImage -value "C:\Custom-Folder\wallpaper.jpg"

Registry keys (theme)

Technical basis

I found that we can simply customize the default theme using the following registry values:

Name	Path	Type	Value
`InstallTheme`	`HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes`	`String`	`<path to theme file>`
`DesktopBackground`	`HKLM\SOFTWARE\\Microsoft\Windows\CurrentVersion\Themes`	`String`	`<path to background file>`
`BrandIcon`	`HKLM\SOFTWARE\\Microsoft\Windows\CurrentVersion\Themes`	`String`	`<path to icon file>`
`ThemeName`	`HK\SOFTWARE\LM\Microsoft\Windows\CurrentVersion\Themes`	`String`	`<THEME NAME>`
`CurrentTheme`	`HKU\<SID>\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes`	`String`	`<path to theme file>`

Theme file:

Default theme path: C:\Windows\resources\Themes\aero.theme

; Copyright © Microsoft Corp.

[Theme]
; Windows - IDS_THEME_DISPLAYNAME_AERO
DisplayName=@%SystemRoot%\System32\themeui.dll,-2013
SetLogonBackground=0

; Computer - SHIDI_SERVER
[CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}\DefaultIcon]
DefaultValue=%SystemRoot%\System32\imageres.dll,-109

; UsersFiles - SHIDI_USERFILES
[CLSID\{59031A47-3F72-44A7-89C5-5595FE6B30EE}\DefaultIcon]
DefaultValue=%SystemRoot%\System32\imageres.dll,-123

; Network - SHIDI_MYNETWORK
[CLSID\{F02C1A0D-BE21-4350-88B0-7367FC96EF3C}\DefaultIcon]
DefaultValue=%SystemRoot%\System32\imageres.dll,-25

; Recycle Bin - SHIDI_RECYCLERFULL SHIDI_RECYCLER
[CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon]
Full=%SystemRoot%\System32\imageres.dll,-54
Empty=%SystemRoot%\System32\imageres.dll,-55

[Control Panel\Cursors]
AppStarting=%SystemRoot%\cursors\aero_working.ani
Arrow=%SystemRoot%\cursors\aero_arrow.cur
Crosshair=
Hand=%SystemRoot%\cursors\aero_link.cur
Help=%SystemRoot%\cursors\aero_helpsel.cur
IBeam=
No=%SystemRoot%\cursors\aero_unavail.cur
NWPen=%SystemRoot%\cursors\aero_pen.cur
SizeAll=%SystemRoot%\cursors\aero_move.cur
SizeNESW=%SystemRoot%\cursors\aero_nesw.cur
SizeNS=%SystemRoot%\cursors\aero_ns.cur
SizeNWSE=%SystemRoot%\cursors\aero_nwse.cur
SizeWE=%SystemRoot%\cursors\aero_ew.cur
UpArrow=%SystemRoot%\cursors\aero_up.cur
Wait=%SystemRoot%\cursors\aero_busy.ani
DefaultValue=Windows Default
DefaultValue.MUI=@main.cpl,-1020

[Control Panel\Desktop]
Wallpaper=%SystemRoot%\web\wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=10
Pattern=

[VisualStyles]
Path=%ResourceDir%\Themes\Aero\Aero.msstyles
ColorStyle=NormalColor
Size=NormalSize
AutoColorization=0
ColorizationColor=0XC40078D7
SystemMode=Dark

[boot]
SCRNSAVE.EXE=

[MasterThemeSelector]
MTSM=RJSPBS

[Sounds]
; IDS_SCHEME_DEFAULT
SchemeName=@%SystemRoot%\System32\mmres.dll,-800

In order to prevent misconfiguration, I suggest to either create a new theme file from the default file or customize the default theme file.

Limitations

No limitation found yet

Code snippet

################################# Global FUNCTIONS ################################################
###################################################################################################
# Define function to update theme file
Function Set-INIValue(){
    param(
        [Parameter(Mandatory=$true, Position=0)] 
        [ValidateNotNullOrEmpty()]
        [string]$INICOntent,

        [Parameter(Mandatory=$true, Position=1)] 
        [ValidateNotNullOrEmpty()]
        [string]$Category,

        [Parameter(Mandatory=$true, Position=2)] 
        [ValidateNotNullOrEmpty()]
        [string]$Key,

        [Parameter(Mandatory=$true, Position=3)] 
        [ValidateNotNullOrEmpty()]
        [string]$Value
    )
    If($INICOntent -match "(?m)^$Key=.*"){
        $INICOntent -Replace "(?m)^$Key=.*","$Key=$Value"
    }Else{
        $INICOntent -Replace "(?m)^\[$Category\]","[$Category]`n$Key=$Value"
    }
}

################################# Customization ####################################################
####################################################################################################

$THEME_NAME = "CORPORATE"
$THEME_FILENAME = "corporate.theme"

# Download theme or copy it from app package
New-Item "C:\Windows\Web\Wallpaper\Corporate" -ItemType Directory -Force | Out-Null
$WALLPAPER_PATH = "C:\Windows\Web\Wallpaper\Corporate\wallpaper.png"
Invoke-WebRequest -Uri "https://wallpaper-house.com/data/out/10/wallpaper2you_388644.png" -OutFile "$WALLPAPER_PATH"

#--------------------------------------------------------------------------------------------------------------#
$THEME=@{
    "Theme:DisplayName"                         =       "CORPORATE"
    "Control Panel\Desktop:Wallpaper"           =       "$WALLPAPER_PATH"
    "Control Panel\Desktop:WallpaperStyle"      =       "10"
    "VisualStyles:SystemMode"                    =      "Dark"
    "VisualStyles:ColorizationColor"            =       "0XC40078D7"
    "VisualStyles:AppMode"                      =       "Dark" 
}
# Doc: https://docs.microsoft.com/en-us/windows/win32/controls/themesfileformat-overview
#--------------------------------------------------------------------------------------------------------------#

################################# Logic ############################################################
####################################################################################################

$THEME_REGISTRY_KEY = "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes"
$THEME_FOLDER = "C:\Windows\resources\Themes"

# Copy Current theme
$currentThemePath = "$(Get-ItemPropertyValue "Registry::$THEME_REGISTRY_KEY" "InstallTheme")"
If("$currentThemePath" -ne "$THEME_FOLDER\$THEME_FILENAME"){
    Copy-Item "$currentThemePath" -Destination "$THEME_FOLDER\$THEME_FILENAME"
}

# Edit theme file

## Get file content
$themeFileContent = Get-Content -Path "$THEME_FOLDER\$THEME_FILENAME" | Out-String


## Customize theme
## Customize theme
ForEach($item in $THEME.Keys){
    $themeFileContent =  Set-INIValue "$themeFileContent" "$(($item -Split ':')[0])" "$(($item -Split ':')[1])" "$($THEME[$item])"
}


## Set file content
$themeFileContent | Out-File -FilePath  "$THEME_FOLDER\$THEME_FILENAME"

# Set as new theme
Set-ItemProperty -Path "Registry::$THEME_REGISTRY_KEY" -Name "ThemeName" -Value "$THEME_NAME"
Set-ItemProperty -Path "Registry::$THEME_REGISTRY_KEY" -Name "InstallTheme" -Value "$THEME_FOLDER\$THEME_FILENAME"

Applying theme to user already logged-in (optional)

Technical basis

In order to apply the theme to the current user, you can use the following code:

rundll32.exe themecpl.dll,OpenThemeAction "C:\path\to\mytheme.theme"
# Source: https://stackoverflow.com/questions/546818/how-do-i-change-the-current-windows-theme-programmatically

This code must be run in the user context, you can use KelvinTegelaar/RunAsUser or create your own system (this is what I choose)

Code snippet

# Define function to execute code as logged-on user
Function Invoke-AsCurrentUser(){
    param(
        [Parameter(Mandatory=$true, Position=0)] 
        [ValidateNotNullOrEmpty()]
        [String]$Script
    )

    # Create random name for task
    $taskName="Invoke-AsCurrentUser-$(Get-Random -Maximum 1000)"

    # Put code in temp file
    $Script | Out-File -FilePath "C:\Users\Public\$taskName.ps1"

    # Define action
    $action = New-ScheduledTaskAction -Execute "powershell.exe" -Argument "-WindowStyle Hidden -Command &{&('C:\Users\Public\$taskName.ps1') ; Remove-Item -Path 'C:\Users\Public\$taskName.ps1'}"
    
    # Define trigger to run the task in 1 minute
    $trigger = New-ScheduledTaskTrigger -AtLogon

    # Define targeted user
    $principal = New-ScheduledTaskPrincipal -UserId (Get-CimInstance –ClassName Win32_ComputerSystem | Select-Object -expand UserName)
    

    $settings = New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries

    # Create task
    $task = New-ScheduledTask -Action $action -Trigger $trigger -Principal $principal -Settings $settings
    
    # Register task
    Register-ScheduledTask $taskName -InputObject $task

    # Start Task
    Start-ScheduledTask -TaskName $taskName

    # Launch process to remove scheduled task in 5 minutes
    Start-Process "powershell.exe" "Invoke-Command -ScriptBlock {Start-Sleep -Seconds 300;Unregister-ScheduledTask -TaskName `"$taskName`" -Confirm:`$false};" -WindowStyle Hidden
    
}


# Set new theme to current user (run in user context)
Invoke-AsCurrentUser -Script (
    
    "`$THEME_FOLDER='$THEME_FOLDER';`$THEME_FILENAME='$THEME_FILENAME';"+
    
    ({
    ## Set theme file using themecpl.dll 'OpenThemeAction' function (https://windows10dll.nirsoft.net/themecpl_dll.html)
    rundll32.exe themecpl.dll,OpenThemeAction "$THEME_FOLDER\$THEME_FILENAME"

    ## Wait for process to start
    $loop=0
    While("$(Get-Process SystemSettings -ErrorAction SilentlyContinue)" -eq ""){
        Start-Sleep -Milliseconds  100
        $loop=+1
        If($loop -ge 10){
            Continue
        }
    }
    Start-Sleep -Seconds 1
    ## Close process
    $loop=0
    While("$(Get-Process SystemSettings -ErrorAction SilentlyContinue)" -ne ""){
        Start-Sleep -Milliseconds  100
        $loop=+1
        If($loop -ge 10){
            Continue
        }
        Get-Process SystemSettings -ErrorAction SilentlyContinue | Stop-Process -force
    }
}).toString())

Final solution

Full code here (lockscreen left as default)

Result

Customize Windows 10+ default theme

Content

Purpose

Study

C# code integration (wallpaper)

Technical basis

Limitations

Code snippet

Registry keys (lockscreen)

Technical basis

Limitations

Code snippet

Registry keys (theme)

Technical basis

Limitations

Code snippet

Applying theme to user already logged-in (optional)

Technical basis

Code snippet

Final solution

Sources / usefull resources