#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : 0xC000021A -- STATUS_SYSTEM_PROCESS_TERMINATED
    Fix   : Disable driver signature enforcement and remove the offending product
    Source: https://jbtecwiz.com/support/win-0xc000021a

    Run as     : WinRE startup settings
    Expect     : 45 minutes
    Risk       : medium
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    A security product or credential provider was installed recently.

    HOW TO UNDO IT
    Export the Credential Providers key before deleting anything, and
    re-import it if the fix was wrong.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 5"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  0xC000021A -- STATUS_SYSTEM_PROCESS_TERMINATED' -ForegroundColor White
Write-Host '  Disable driver signature enforcement and remove the offending product' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: medium   Reversible   45 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'In WinRE choose Troubleshoot -> Advanced options -> Startup Settings -> Restart, then press 7 for Disable driver signature enforcement.' -Why '0xC000021A is frequently a third-party module that winlogon loads. This is often the only way to reach a desktop long enough to remove it.' -Manual

Invoke-Step -Number 2 -Do 'If that boots, uninstall the security product with the vendor''s removal tool.' -Manual

Invoke-Step -Number 3 -Do 'If it does not, boot to WinRE Command Prompt and check for third-party credential providers.' -Command {
    cmd.exe /c 'reg load HKLM\OFF D:\Windows\System32\config\SOFTWARE & reg query "HKLM\OFF\Microsoft\Windows\CurrentVersion\Authentication\Credential Providers"'
}

Invoke-Step -Number 4 -Do 'Note any GUID that is not a Microsoft one, then delete that key.' -Command {
    cmd.exe /c 'reg delete "HKLM\OFF\Microsoft\Windows\CurrentVersion\Authentication\Credential Providers\{GUID}" /f & reg unload HKLM\OFF'
}

Invoke-Step -Number 5 -Do 'Restart.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'Windows boots normally with signature enforcement back on.' 'White'

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/win-0xc000021a' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Export the Credential Providers key before deleting anything, and re-import it if the fix was wrong.' 'DarkGray'
Write-Rule