Compare UserPrincipalName and Primary Email Address in Active Directory and Flag Discrepancies

This script retrieves all Active Directory users along with their properties such as proxy addresses, userPrincipalName, and last logon timestamp. It compares each user's `userPrincipalName` (UPN) with their primary email address (extracted from the `proxyAddresses` field). If the primary email and UPN differ, the script flags the user by adding a `ChangeUPN` property. The script also calculates and formats the `LastLogonTimeStamp` for each user. It includes optional logic to update UPNs, but this part is currently commented out.

Here is the script:

#$exclude = "DiscoverySearchMailbox {D919BA05-46A6-415f-80AD-7E09334BB852}","Administrator","Public Folder"
$allUsers = Get-ADUser -f * -SearchBase "CN=Users,DC=XXX-Forest,DC=local" -Properties proxyAddresses,mail,userPrincipalName,lastlogontimestamp

$Property = $allUsers | Get-Member -Type Property |Where-Object Name -ne "LastLogonTimeStamp"|Select-Object -ExpandProperty Name
$Property += @{Name="LastLogonTimeStamp";Expression={([datetime]::FromFileTime($_.LastLogonTimeStamp))}}
$allUsers = $allUsers | Select-Object -Property $Property
#$AllUsersToChangeUPN = @()

$allUsers | ForEach-Object {
#    if($_.name -notin $exclude){
        $UPN = $_.userPrincipalName
        $PEmail = $_.proxyAddresses | Where-Object {$_ -CLike "SMTP:*"}
        if($PEmail) {
            $PEmail = ($PEmail.split(':'))[1]
            if($PEmail -ne $UPN) {
                #Write-Host "UPN: $UPN diffent then Email: $PEmail"
                #$AllUsersToChangeUPN += $_
                $ChangeUPN = $true
            } else {
                $ChangeUPN = $false
            }
        }
#    }
    $_ | Add-Member -Name 'PrimaryEmail' -Value $PEmail -MemberType NoteProperty
    $_ | Add-Member -Name 'ChangeUPN' -Value $ChangeUPN -MemberType NoteProperty
}

<#
$AllUsersToChangeUPN | ForEach-Object {
    $PEmail = $_.proxyAddresses | Where-Object {$_ -CLike "SMTP:*"}
    $_ | Set-ADUser -UserPrincipalName $PEmail -WhatIf
}

$allUsers = Get-ADUser -f * -SearchBase "CN=Users,DC=xxx-Forest,DC=local" -Properties lastlogontimestamp,proxyAddresses,mail,userPrincipalName 
$Property = $allUsers | Get-Member -Type Property |Where-Object Name -ne "LastLogonTimeStamp"|Select-Object -ExpandProperty Name
$Property += @{Name="LastLogonTimeStamp";Expression={([datetime]::FromFileTime($_.LastLogonTimeStamp))}}
$allUsers = $allUsers | Select-Object -Property $Property

$Now = Get-Date
$date = $Now.AddMonths(-8)
$allUsers | Where-Object LastLogonTimeStamp -lt $date | Where-Object Enabled | ft -AutoSize Name,LastLogonTimeStamp,Enabled
#>