Change user mail property with ADSI in PowerShell - powershell

Question

I am trying to update the email address of a directory user with PowerShell.
I am unable to modify the mail property of a user entry with the following code:
$BadUser = [adsi] $Account.Path
$BadUser.mail.Clear()
$BadUser.mail.Add($User.Email) | Out-Null
$BadUser.SetInfo()
The mail.Clear() nor the mail.Add() seem to modify $BadUser when debugging with PowerGUI.
I have a working version that relies on the QAD plugin, and I would like to avoid using it if possible.
$suf = $AD.Parent.Substring(10)
Connect-QADService -Service "$($AD.dc[0]).$suf" -ErrorVariable AD_Conn_Error -ErrorAction Stop -WarningAction Stop | Out-Null
Set-QADObject $Account.Properties.distinguishedname[0] -ObjectAttributes #{mail=$User.Email} | Out-Null
Disconnect-QADService
Reasons I am avoiding QAD:
I am searching for users across 8 domain servers
ADSI allows me to save multiple connected entries in a list
QAD can connect to 1 domain at a time
ADSI seems relatively fast
QAD has memory leaks (1kB/s bad) that crash in large batches
QAD is unable to "identify" some users that ADSI found by cn

Answer 1

Here's some example code to do it:
$query= "(&(objectCategory=User)(cn=FirstName LastName))"
$OU = "LDAP://OU=Users,dc=subdomain,dc=company,dc=com"
$PageSize = 100
$objOU = New-Object System.DirectoryServices.DirectoryEntry($OU)
$objSearcher = New-Object System.DirectoryServices.DirectorySearcher
$objSearcher.SearchRoot = $objOU
$objSearcher.PageSize = $PageSize
$objSearcher.Filter = $query
$objSearcher.SearchScope = "Subtree"
$colResults = $objSearcher.FindAll()
foreach($objResult in $colResults) {
$dirObject = [ADSI]$objResult.GetDirectoryEntry()
$dirObject.mail = "newaddress#company.com"
$dirObject.CommitChanges()
}