To start with I need to create the UPNS in AD and then exported a list of users Get-Mailbox -ResultSize Unlimited |Select-Object UserPrincipalName,PrimarySmtpAddress, @{Name=“EmailAddresses”;Expression={$_.EmailAddresses |Where-Object {$_.PrefixString -ceq “smtp”} | ForEach-Object {$_.SmtpAddress}}} | Export-CSV c:\temp\exportsmtpUserPrincipalName.csv -NoTypeInformation Once I had my list of users in different txt...