Using regex to validate email address in powershell

Question

So i made a script that parses a .msg file in outlook and ommits the result. The whole scripts works except for when I receive an email from inside the network (we use Active Directory) is when i get a result similar to this: /O=Business/OU=FIRST ADMINISTRATIVE GROUP/CN=RECIPIENTS/CN=MIKEF otherwise for emails outside the network I get email@email.com. I would like to to validate this this with regex that way it would take the name in the CN=" " and adds it to my @email.com

$MSGFILEPATH = '\\srv01\FTP\EmailtoSupportPortal\Testing'
$MSGCOMPLETED= '\\srv01\FTP\EmailtoSupportPortal\Testing\Completed'
Function MSGFiles {
Get-ChildItem $MSGFILEPATH -Filter *.msg|`
ForEach-Object{
    $outlook = New-Object -comobject outlook.application
    $msg = $outlook.CreateItemFromTemplate($_.FullName)
    $body = $msg.Body
    $SEM = $msg.SenderEmailAddress
    $Subject = $msg.Subject 
    $SEM
    }
}
MSGFiles

Answer 1

Check the MailItem.SenderEmailType property. If it is "EX", use MailItem.Sender.GetExchangeUser.PrimarySmtpAddress (be prepared to handle nulls/errors). Otherwise use the SenderEmailAddress property the way you do that now.