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

    Fault : ERR_PROXY_CONNECTION_FAILED -- a proxy is set that should not be
    Fix   : Find the policy that keeps putting it back
    Source: https://jbtecwiz.com/support/win-net-proxy

    Run as     : Elevated PowerShell
    Expect     : 20 minutes
    Risk       : medium
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    The setting is greyed out, or returns after a restart or a Group Policy
    refresh.

    HOW TO UNDO IT
    Export the keys with reg export before deleting them; re-import to
    restore.

    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 3"
    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 '  ERR_PROXY_CONNECTION_FAILED -- a proxy is set that should not be' -ForegroundColor White
Write-Host '  Find the policy that keeps putting it back' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: medium   Reversible   20 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 'Check for the policy keys that lock the page.' -Command {
    Get-ItemProperty 'HKLM:\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings' -ErrorAction SilentlyContinue
    Get-ItemProperty 'HKCU:\Software\Policies\Microsoft\Internet Explorer\Control Panel' -ErrorAction SilentlyContinue
}

Invoke-Step -Number 2 -Do 'On a domain machine, find which GPO is responsible rather than deleting the key.' -Why 'Deleting a policy-set value on a domain machine fixes it until the next refresh, at most 90 minutes away. The report names the GPO so it can be corrected once, centrally.' -Command {
    cmd.exe /c 'gpresult /h %USERPROFILE%\Desktop\gpo.html & start %USERPROFILE%\Desktop\gpo.html'
}

Invoke-Step -Number 3 -Do 'On a machine that has left a domain and kept the settings, remove the stale policy keys.' -Command {
    Remove-Item 'HKCU:\Software\Policies\Microsoft\Internet Explorer' -Recurse -Force -ErrorAction SilentlyContinue
    gpupdate /force
}

Write-Rule "  Confirm it worked"
Show-Prose 'The proxy page is editable and stays clear after a restart.' '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-net-proxy' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Export the keys with reg export before deleting them; re-import to restore.' 'DarkGray'
Write-Rule