Exchange Global Address List Not Updating - Force Global Address List (GAL) Update

I have created this Powershell script to be able to force an update of the Global Address List within Exchange 2007. After making changes to recipients/distribution lists within Exchange, I sometimes required a way to make these changes quickly accessible to users, so when they next download the GAL through Outlook, they obtain the latest changes. Most environments do this automatically once or twice a day, which is fine, but this script can be used to force the process to run as required.

Before running this script, I manually force an update of the Default Offline Address Book (OAB) through the Exchange Management Console. I then run this script to force the latest version of the OAB to the Client Access Server's so it is available for download by end users.


#Enable Exchange cmdlets
add-pssnapin *exchange* -erroraction SilentlyContinue

#Force Update of OAB
Get-OfflineAddressBook | Update-OfflineAddressBook

#Get List of Current CAS Servers
$CASList = Get-ExchangeServer | where {$_.isClientAccessServer -eq $true}

#Force Deployment of GAL to CAS's
ForEach ($CAS in $CASList)
    {
    Update-FileDistributionService $($CAS.Name)
    }