Disable User Access Account (UAC) using PowerShell

Disable-UAC.ps1

function Disable-UAC(){
    $numVersion = (Get-CimInstance Win32_OperatingSystem).Version
    $numSplit = $numVersion.split(".")[0]
 
    if ($numSplit -eq 10) {
        Set-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "ConsentPromptBehaviorAdmin" -Value "0"
    }
    elseIf ($numSplit -eq 6) {
        $enumSplit = $numSplit.split(".")[1]
        if ($enumSplit -eq 1 -or $enumSplit -eq 0) {
            Set-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "EnableLUA" -Value "0"
        } else {
            Set-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "ConsentPromptBehaviorAdmin" -Value "0"
        }
    }
    elseIf ($numSplit -eq 5) {
        Set-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "EnableLUA" -Value "0"
    }
    else {
        Set-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "ConsentPromptBehaviorAdmin" -Value "0"
    }
    Write-Host "Successfully Disabled UAC!"
}

Thank you for sharing.

For Windows 10, I found the registry key values allow you to set different levels from the UAC settings. Here is what I found.

UAC Settings
Control Panel\All Control Panel Items\Security and Maintenance => User Account Control Settings

Registry location:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

The following values on "ConsentPromptBehaviorAdmin" and "PromptOnSecureDesktop" for different levels of UAC settings.

"ConsentPromptBehaviorAdmin"
-Value 
    0 : (Not recommended - Lowest) Never notify me when 
                                - "PromptOnSecureDesktop" -Value "0"

    5 : (Not recommended) Notify me only when apps try to make changes to my computer (Do not dim my desktop)
                                - "PromptOnSecureDesktop" -Value "0"

    5 : (Recommended) Notify me only when apps try to make changes to my computer (default)
                                - Don't notify me when I make changes to Windows settings 
                                - "PromptOnSecureDesktop" -Value "1"

    2 : (Recommended - highest level ) Always notify me when:  
                                - Apps try to install software or make changes to my computer 
                                - I make changes to Windows settings
                                - "PromptOnSecureDesktop" -Value "1"

This script makes no sense. UAC was introduced with Windows Vista/Windows Server 2008, i.e. $numSplit -eq 6 -and $enumSplit -eq 0.

Trying to check and change UAC on $numSplit -eq 5 (Windows 2000 to Windows Server 2003 R2) in line 16 ... 18 is useless...

The only special cases the script handles seems to be for 6.0 and 6.1 where the script sets EnableLUA to 0.
In all other cases the script changes ConsentPromptBehaviorAdmin instead...