# imports emails into CSV from a CSV containing DisplayName

$CSVFile = 'C:\Users\eeckert\Downloads\MS Project.csv'

$csvdata = Import-Csv $CSVFile

foreach ($item in $csvdata) {
    $dname = $item.'Computer Current User Display Name' 
    $Filter = "DisplayName -eq '$dname'"
    try {$item.Email = (Get-ADUser -Filter $Filter -Properties mail).mail}
    catch {$item.email = 'lookup Failed'}
    
}

# $emails = $csvdata.Email   

$csvdata | Export-Csv -Path $CSVFile