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

    Fault : 0xC000021A -- STATUS_SYSTEM_PROCESS_TERMINATED
    Fix   : Repair the system files offline
    Source: https://jbtecwiz.com/support/win-0xc000021a

    Run as     : Windows Recovery Environment
    Expect     : 45-60 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    After a power loss, or when nothing else fits.

    HOW TO UNDO IT
    None -- these repair in place.

    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 '  Repair the system files offline' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   45-60 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 'From WinRE Command Prompt, identify the Windows volume as above.' -Manual

Invoke-Step -Number 2 -Do 'Check the disk first -- a filesystem error will make the repair fail confusingly.' -Command {
    cmd.exe /c 'chkdsk D: /f /r'
}

Invoke-Step -Number 3 -Do 'Run the offline system file check. Both paths are required and both are easy to get wrong.' -Why 'offbootdir is the drive holding the boot files, offwindir the one holding \Windows. On most machines in WinRE they are the same letter, but not always.' -Command {
    cmd.exe /c 'sfc /scannow /offbootdir=D:\ /offwindir=D:\Windows'
}

Invoke-Step -Number 4 -Do 'Repair the component store from a mounted ISO of the same build if SFC reports it could not fix everything.' -Command {
    cmd.exe /c 'DISM /Image:D:\ /Cleanup-Image /RestoreHealth /Source:WIM:E:\sources\install.wim:1 /LimitAccess'
}

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

Write-Rule "  Confirm it worked"
Show-Prose 'Windows boots and a subsequent online sfc /scannow reports no violations.' '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: None -- these repair in place.' 'DarkGray'
Write-Rule