Block Outlook for Windows PowerShell

Question

Hi All,

Does anyone has a PowerShell script that will block users from upgrading to the new Outlook for Windows client if they haven't switched yet? Anyone that has upgraded should remain on the new version.

Thanks

Answer 1

Hi @Louis Rush ，

Does anyone has a PowerShell script that will block users from upgrading to the new Outlook for Windows client if they haven't switched yet? Anyone that has upgraded should remain on the new version.

As far as I know, there's no PowerShell Script that can meet this requirement in all details. Generally, we can disable users' access to the new Outlook by running the Set-CASMailbox cmdlet and setting the OneWinNativeOutlookEnabled property to $false. But it's hard to exclude users who have already switched to the New Outlook as this requires touching the registry settings on the users' local machines.

Given this, instead of using PowerShell, personally I'd suggest just hiding the New Outlook toggle in Outlook Desktop for all users by configuring the registry key though group policy (GPO):

(Important: Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.)

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General]
"HideNewOutlookToggle"=dword:00000001

With this registry implemented, users who have switched to the New Outlook will remain using it, and the others will be unable to access the New Outlook version as they cannot see the toggle.

Here's an official article for reference in case you have the interest to learn more about the administrative tasks about the New Outlook.

Enable or disable employee access to the new Outlook for Windows

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