The current solid color setting for Windows desktop is stored in the registry at:

HKEY_CURRENT_USER\Control Panel\Colors\Background

This REG_SZ value contains three decimal numbers (0-255) representing the RGB components of your background color, separated by spaces.

To check your current setting:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Control Panel\Colors]
"Background"="58 110 165"

The example above shows a medium blue color (R=58, G=110, B=165).

Create a .reg file with this content to change to pure red:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Control Panel\Colors]
"Background"="255 0 0"

For automation, use this PowerShell script:

$colorValue = "0 128 64"  # Dark green
Set-ItemProperty -Path "HKCU:\Control Panel\Colors" -Name "Background" -Value $colorValue
Stop-Process -Name explorer -Force  # Restart Explorer to apply changes

For developers working with .NET:

using Microsoft.Win32;

void SetDesktopColor(byte r, byte g, byte b)
{
    RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Colors", true);
    key.SetValue("Background", $"{r} {g} {b}");
    key.Close();
    // Restart Explorer.exe or refresh the desktop
}

• Changes take effect after restarting Explorer.exe or logging out
• This only affects solid color backgrounds (not wallpapers)
• Create a restore point before modifying registry
• Windows may override these settings during theme changes

For more reliable changes, use the Win32 API:

[DllImport("user32.dll", SetLastError = true)]
static extern bool SystemParametersInfo(uint uiAction, uint uiParam, uint pvParam, uint fWinIni);

void SetDesktopColorWin32(byte r, byte g, byte b)
{
    uint color = (uint)((r << 16) | (g << 8) | b);
    SystemParametersInfo(0x0014, 0, color, 0x01 | 0x02);
}

The solid color background setting in Windows is stored in the registry under:
HKEY_CURRENT_USER\Control Panel\Colors
The specific value you need to modify is Background, which contains the RGB values in the format "R G B" (e.g., "58 110 165" for a blue color).


To manually change the desktop color through Registry Editor:

Press Win+R, type regedit and hit Enter
Navigate to HKEY_CURRENT_USER\Control Panel\Colors
Double-click the Background value
Enter your desired RGB values separated by spaces
Log off and back on for changes to take effect



Here's a C# implementation to change the desktop color programmatically:
using Microsoft.Win32;
using System;

class DesktopColorChanger
{
    static void Main(string[] args)
    {
        try
        {
            RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Colors", true);
            key.SetValue("Background", "100 150 200"); // Example: light blue
            key.Close();
            
            // Refresh the desktop
            System.Diagnostics.Process.Start("rundll32.exe", "user32.dll,UpdatePerUserSystemParameters");
            
            Console.WriteLine("Desktop color changed successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
    }
}

For those preferring PowerShell:
Set-ItemProperty -Path "HKCU:\Control Panel\Colors" -Name "Background" -Value "200 100 50"
$signature = @"
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern int SystemParametersInfo(int uAction, int uParam, string lpvParam, int fuWinIni);
"@
$systemParamInfo = Add-Type -MemberDefinition $signature -Name Win32SPI -Namespace Win32Functions -PassThru
$systemParamInfo::SystemParametersInfo(0x0014, 0, $null, 1)


The change won't be visible immediately - you need to either log off/on or refresh the desktop
This only works for solid colors, not for wallpaper images
On Windows 10/11, this might be overridden by themes or personalization settings
Always back up the registry before making changes

If you need to convert from hex color codes to the RGB format Windows expects:
public static string HexToRegistryRgb(string hexColor)
{
    if (hexColor.StartsWith("#")) hexColor = hexColor.Substring(1);
    
    int r = Convert.ToInt32(hexColor.Substring(0, 2), 16);
    int g = Convert.ToInt32(hexColor.Substring(2, 2), 16);
    int b = Convert.ToInt32(hexColor.Substring(4, 2), 16);
    
    return $"{r} {g} {b}";
}

If you encounter permission issues when writing to the registry, you may need to:
RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Colors", true);
if (key == null)
{
    // Create the key if it doesn't exist
    key = Registry.CurrentUser.CreateSubKey(@"Control Panel\Colors");
}