Hide AD User in GAL (without Exchange Server Schema Attributes)

Below is a custom script to hide an AD user from GAL (global address list) when Exchange Server schema has been removed from Active Directory. 

##############################################################

# This Scrip will allow you to hide a mailbox in Ad #

##############################################################

#Add AD functionality.

Import-Module ActiveDirectory

#Request username to use in distribution group search.

Write-Host "Enter username, or 'exit' to close."

$User = Read-Host

#Check for exit request.

if (($User -eq "exit") -or ($User -eq "Exit") -or ($User -eq "EXIT")) {

exit

}

#If no exit command is entered, search for the requested user.

while (($User -ne "exit") -and ($User -ne "Exit") -and ($User -ne "EXIT")) {

$UserExists = Get-ADUser -filter {sAMAccountName -eq $User}

#Check if user exists, and skip search if they do not.

if (!$UserExists) {

Write-Host "ERROR: That user does not exist."

}

Else {

#command to complete

Set-ADUser $User -Replace @{msExchHideFromAddressLists=$true}

}

#Request new user or app exit.

Write-Host "`nEnter username, or 'exit' to close."

$User = Read-Host

}