Office 365 – msExchHideFromAddressLists does not synchronize with Office 365

💡 How to make sure HiddenFromAddressListsEnabled works as expected?

• 💡 Active Directory has Exchange Extended Schema – this can be done by downloading Exchange 2016 CU15 or similar and executing Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareSchema command

• 💡 Exchange hybrid deployment is selected in Azure AD Connect

• 💡 Run Initial Synchronization after any change of configuration

Start-ADSyncSyncCycle -PolicyType Initial

• 💡 Update msExchHideFromAddressLists for each user that you want to hide from GAL (set TRUE as value)
• 💡 Refresh directory schema with any change to AD Schema

• 💡 Update mailNickName attribute to proper, non-empty value

$WhatIf = $true
$Forest = Get-ADForest
foreach ($Domain in $Forest.Domains) {
    $Users = Get-ADUser -Filter { Mail -like '*' -and MailNickName -notlike '*' } -Properties mailNickName, mail,msExchHideFromAddressLists -Server $Domain
    $Users | Format-Table -AutoSize Name, SamAccountName, DisplayName, Mail,mailNickName, Enabled, msExchHideFromAddressLists,DistinguishedName
    foreach ($_ in $Users) {
        Set-ADUser -Identity $_ -Replace @{mailNickname = $_.SamAccountName } -Server $Domain -WhatIf:$WhatIf
    }
}