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

    Fault : The Teams Meeting button is missing from Outlook
    Fix   : Re-enable an add-in that is listed but inactive
    Source: https://jbtecwiz.com/support/win-office-teams-addin

    Run as     : PowerShell as the affected user
    Expect     : 20 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    The add-in appears in the Add-ins list as inactive or disabled.

    HOW TO UNDO IT
    Set LoadBehavior back to 0 to disable the add-in again.

    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.
#>

[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 '  The Teams Meeting button is missing from Outlook' -ForegroundColor White
Write-Host '  Re-enable an add-in that is listed but inactive' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   20 minutes'
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 'Close Outlook.' -Command {
    Get-Process OUTLOOK -ErrorAction SilentlyContinue | Stop-Process -Force
}

Invoke-Step -Number 2 -Do 'Read the current LoadBehavior.' -Why '3 is loaded at startup. 2 means Outlook tried it, it failed, and it was turned off. 0 means someone disabled it deliberately.' -Command {
    Get-ItemProperty 'HKCU:\Software\Microsoft\Office\Outlook\Addins\TeamsAddin.FastConnect' -ErrorAction SilentlyContinue | Select-Object LoadBehavior, Description
}

Invoke-Step -Number 3 -Do 'Set it back to load at startup.' -Command {
    Set-ItemProperty 'HKCU:\Software\Microsoft\Office\Outlook\Addins\TeamsAddin.FastConnect' -Name LoadBehavior -Type DWord -Value 3
}

Invoke-Step -Number 4 -Do 'Clear the resiliency lists, which override LoadBehavior and are the reason it keeps reverting to 2.' -Why 'Setting LoadBehavior to 3 without clearing these puts it straight back to 2 on the next start, which is why this fix appears not to work when only half of it is done.' -Command {
    Remove-Item 'HKCU:\Software\Microsoft\Office\16.0\Outlook\Resiliency\DisabledItems' -Recurse -Force -ErrorAction SilentlyContinue
    Remove-Item 'HKCU:\Software\Microsoft\Office\16.0\Outlook\Resiliency\CrashingAddinList' -Recurse -Force -ErrorAction SilentlyContinue
}

Invoke-Step -Number 5 -Do 'Start Outlook and confirm the button is back.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'LoadBehavior still reads 3 after two restarts, and the button is present.' 'White'
Write-Host ''
if (-not $DryRun) {
    Get-ItemProperty 'HKCU:\Software\Microsoft\Office\Outlook\Addins\TeamsAddin.FastConnect' | Select-Object LoadBehavior
}

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-office-teams-addin' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Set LoadBehavior back to 0 to disable the add-in again.' 'DarkGray'
Write-Rule