Updated July 28,February 10, 2025: We have updated the content, timeline, and additional resources.content. Thank you for your patience.
We are changing how you enable or disable the recommended methodnew Microsoft Outlook for disablingWindows and Microsoft Outlook for the web so that users can continue to access the new Outlook for Windows.web.
When this will happen:
There is no change that isGeneral Availability (Worldwide, GCC): We will begin rolling out. We have published a new support article with instructions on howout late February 2025 (previously late January) and expect to use our existing infrastructure to block users from access Outlook for the web without impacting Outlook for Windows.complete by mid-March 2025 (previously mid-February).
How this will affect your organization:
Admins can followWe're changing the instructions in this support article to blockCASMailbox -OWAEnabled parameter that enables or disables access to user mailboxes using Outlook for the web using Conditional Access. Blocking(formerly known as Outlook Web App or OWA) to block only Outlook for the web using this policy has no impact onand to not affect the behavior of new Outlook for Windows.
OnceYou can manage new Outlook for Windows with the CASMailbox-OneWinNativeOutlookEnabled policy.
You are receiving this message because our reporting indicates one or more users in your organization may be using the New Outlook for Windows.
Note: We will not change any existing value for the settings, but we will change which setting controls if the new Outlook for Windows is allowed for the user. Before this rollout, both CASMailbox-OWAEnabled and CASMailboxOneWinNativeOutlookEnabled policies are checked. After this rollout, we will remove the check for CASMailbox-OWAEnabled so you can have the chance to enable new Outlook and still disable Outlook for the web is blocked, admins can set the CASMailbox policy -OWAEnabled to $true. This will have no impact on users' ability to access outlook for the web since the work was already done to block Outlook for the web with another policy.
if desired.
What you need to do to prepare:
There areThis rollout will happen automatically by the specified date with no changesadmin action required before the rollout. Review your current configuration to existing polices, so theredetermine the impact for your organization. You may want to notify your admins about this change and update any relevant documentation.
After this change takes effect, please confirm the CASMailbox OneWinNativeOutlookEnabled policy state for each mailbox. The default value is nothing you need to do to prepare.Enabled.
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