If you are taking over an Active Directory or just trying to run cleanup on one that you currently manage, one of the tasks you will probably want to perform is to check to see which of the built-in schema ExtensionAttributes are in use.

If you don’t have ExtensionAttributes 1-15 in your On Premises Active Directory you will need to extend your schema for Exchange Server.

The script below has also been added to my github.

https://github.com/paularquette/Active-Directory

#Check Computers
$i = 1
while ($i -lt 16)
{
$exAtrib = "extensionAttribute"
$exAtrib = $exAtrib + "$i"
Write-Host "Checking Computers for $exAtrib"
$inUse = Get-ADComputer -Properties $exAtrib -Filter "$exAtrib -like '*'" |Select Name,$exAtrib

if ($inUse)
{
     Write-Host "Computer Check - $exAtrib is in use"
} else {
     Write-Host "Computer Check - $exAtrib is NOT in use"
}

$i = $i + 1
}
############################################
#Check Groups
$i = 1
while ($i -lt 16)
{
$exAtrib = "extensionAttribute"
$exAtrib = $exAtrib + "$i"
Write-Host "Checking Groups for $exAtrib"
$inUse = Get-ADGroup -Properties $exAtrib -Filter "$exAtrib -like '*'" |Select Name,$exAtrib

if ($inUse)
{
     Write-Host "Group Check - $exAtrib is in use"
} else {
     Write-Host "Group Check - $exAtrib is NOT in use"
}

$i = $i + 1
}
############################################
#Check Users
$i = 1
while ($i -lt 16)
{
$exAtrib = "extensionAttribute"
$exAtrib = $exAtrib + "$i"
Write-Host "Checking Users for $exAtrib"
$inUse = Get-ADUser -Properties $exAtrib -Filter "$exAtrib -like '*'" |Select Name,$exAtrib

if ($inUse)
{
     Write-Host "User Check - $exAtrib is in use"
} else {
     Write-Host "User Check - $exAtrib is NOT in use"
}

$i = $i + 1
}