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

    Fault : USN rollback -- event 2095 and a controller that stops replicating
    Fix   : Take it out of service and rebuild it
    Source: https://jbtecwiz.com/support/srv-id-usn-rollback

    Run as     : Elevated PowerShell
    Expect     : 3-4 hours
    Risk       : high
    Reversible : NO -- read the undo note below before running

    WHEN THIS IS THE RIGHT FIX
    Event 2095 has been logged. There is no supported repair; this is the
    procedure.

    HOW TO UNDO IT
    None. This is a rebuild by design.

    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 6"
    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 '  USN rollback -- event 2095 and a controller that stops replicating' -ForegroundColor White
Write-Host '  Take it out of service and rebuild it' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: high   NOT REVERSIBLE   3-4 hours' -ForegroundColor Yellow
Write-Host ''
Show-Prose 'Undo: None. This is a rebuild by design.' 'Yellow'
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 'Disconnect the affected controller from the network immediately.' -Why 'Objects created on it since the rollback exist nowhere else, and objects deleted elsewhere may still exist on it. Every minute it stays connected increases the divergence.' -Manual

Invoke-Step -Number 2 -Do 'Confirm the diagnosis.' -Command {
    Get-WinEvent -LogName 'Directory Service' -MaxEvents 100 | Where-Object Id -in 2095,2103,1113 | Format-List TimeCreated,Id,Message
}

Invoke-Step -Number 3 -Do 'Identify anything created on this controller since the rollback, so it can be recreated afterwards.' -Command {
    Get-ADObject -Filter { whenCreated -gt $((Get-Date).AddDays(-7)) } -Properties whenCreated,whenChanged | Format-Table Name,ObjectClass,whenCreated
}

Invoke-Step -Number 4 -Do 'Check whether it holds any FSMO roles or is the only global catalog for its site.' -Command {
    netdom query fsmo
    Get-ADDomainController -Filter * | Format-Table Name,Site,IsGlobalCatalog,OperationMasterRoles
}

Invoke-Step -Number 5 -Do 'Force-demote it, clean the metadata from a healthy controller, then rebuild and re-promote from clean media.' -Command {
    Uninstall-ADDSDomainController -ForceRemoval -Force -LocalAdministratorPassword (Read-Host -AsSecureString)
}

Invoke-Step -Number 6 -Do 'Change how this controller is backed up. Snapshots are not a backup for a domain controller -- use Windows Server Backup with system state, or a backup product that is Active Directory aware and uses the VM Generation ID.' -Why 'Without changing the backup method, this will happen again the next time somebody rolls back a snapshot to test something. That is by far the most common cause.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'The rebuilt controller replicates in both directions and no 2095 events appear.' 'White'
Write-Host ''
if (-not $DryRun) {
    repadmin /replsummary
    Get-WinEvent -LogName 'Directory Service' -MaxEvents 50 | Where-Object Id -eq 2095 | Measure-Object
}

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/srv-id-usn-rollback' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: None. This is a rebuild by design.' 'DarkGray'
Write-Rule