#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- read-only diagnostic

    Fault : "Cannot start Microsoft Outlook. Cannot open the Outlook window"
    Source: https://jbtecwiz.com/support/win-office-outlook-wont-start

    This script CHANGES NOTHING. It runs only the inspection commands
    from the write-up -- the Get-, Test- and Resolve- calls that
    establish which cause is in play -- and prints what each returned.
    Anything that writes, deletes, starts or stops is excluded by
    construction, not by judgement.

    Read the output alongside the write-up, then pick the fix that
    matches. Each fix has its own script on the same page.
#>

[CmdletBinding()] param([switch]$Transcript)
$ErrorActionPreference = 'Continue'

if ($Transcript) {
    $log = Join-Path $env:USERPROFILE ("jbtecwiz-win-office-outlook-wont-start-" + (Get-Date -Format yyyyMMdd-HHmmss) + ".txt")
    Start-Transcript -Path $log | Out-Null
    Write-Host ('  Saving a transcript to ' + $log)
}

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

function Probe { param([string]$Label, [string]$Fix, [scriptblock]$Command)
    Write-Rule ("  " + $Label)
    Write-Host ("  from: " + $Fix) -ForegroundColor DarkGray
    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor DarkGreen
    }
    Write-Host ''
    try {
        $out = & $Command 2>&1 | Out-String
        if ([string]::IsNullOrWhiteSpace($out)) {
            Write-Host '    (returned nothing)' -ForegroundColor DarkGray
        } else {
            foreach ($l in ($out.TrimEnd() -split "`n")) { Write-Host ("    " + $l.TrimEnd()) }
        }
    } catch {
        Write-Host ("    could not run: " + $_.Exception.Message) -ForegroundColor Yellow
    }
}

Write-Rule
Write-Host '  "Cannot start Microsoft Outlook. Cannot open the Outlook window"' -ForegroundColor White
Write-Host '  Read-only diagnostic -- nothing is changed.' -ForegroundColor Green
Write-Rule

Probe -Label 'Look at the navigation pane file before deleting it, so you know whether it is the problem.' -Fix 'Reset the navigation pane' -Command {
    Get-ChildItem "$env:APPDATA\Microsoft\Outlook" -Filter '*.xml' | Select-Object Name, Length, LastWriteTime
}

Probe -Label 'List what is registered to load, so you know what you are bisecting.' -Fix 'Find the add-in that is failing at startup' -Command {
    Get-ChildItem 'HKCU:\Software\Microsoft\Office\Outlook\Addins','HKLM:\SOFTWARE\Microsoft\Office\Outlook\Addins' -ErrorAction SilentlyContinue | ForEach-Object { [pscustomobject]@{ Addin = $_.PSChildName; LoadBehavior = (Get-ItemProperty $_.PSPath).LoadBehavior } }
}

Probe -Label 'Record the account details and the path of any PST files in use before you start.' -Fix 'Build a new mail profile' -Command {
    Get-ChildItem 'HKCU:\Software\Microsoft\Office\16.0\Outlook\Profiles' | Select-Object PSChildName
}

Write-Rule
Write-Host '  Diagnostic finished. Nothing was changed.' -ForegroundColor Green
Write-Host ''
Write-Host '  Compare the output above with the write-up, then run the'
Write-Host '  script for the fix that matches:'
Write-Host '    https://jbtecwiz.com/support/win-office-outlook-wont-start'
Write-Rule
if ($Transcript) { Stop-Transcript | Out-Null }