check before: 2025-02-28
Product:
Exchange, Microsoft 365 Apps, Microsoft 365 for the web, Outlook
Platform:
Online, US Instances, Web, World tenant
Status:
Change type:
Admin impact, Updated message, User impact
Links:

Details:
Summary:
Microsoft is updating the process to enable/disable new Outlook for Windows and Outlook for the web, starting late January 2025. The rollout will change the CASMailbox parameters, separating the controls for web and Windows versions. Organizations should review configurations and update documentation accordingly. No admin action is required before the rollout.
Details:
Updated January 29, 2025: We have updated the rollout timeline below. Thank you for your patience.
We are changing how you enable or disable the new Microsoft Outlook for Windows and Microsoft Outlook for the web.
[When this will happen:]
General Availability (Worldwide, GCC): We will begin rolling out late February 2025 (previously late January) and expect to complete by mid-March 2025 (previously mid-February).
Change Category:
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Scope:
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Release Phase:
Created:
2024-11-01
updated:
2025-01-30
Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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MS Urgency
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MS workload name
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summary for non-techies**
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Direct effects for Operations**
Change in Access Control
The change in CASMailbox parameters may lead to confusion regarding which version of Outlook is enabled or disabled, potentially resulting in users being unable to access their email through the web version.
- roles: IT Administrators, End Users
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Documentation Updates
Organizations will need to update their internal documentation to reflect the new parameters and settings, which may lead to temporary inconsistencies in user guidance.
- roles: IT Administrators, Support Staff
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
User Experience Disruption
Users may experience disruptions in their workflow if they are not informed about the changes, leading to frustration and decreased productivity.
- roles: End Users, Team Leaders
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Potential Email Access Issues
If the CASMailbox settings are not reviewed and updated accordingly, users may face issues accessing their emails, particularly through the web version of Outlook.
- roles: IT Administrators, End Users
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Increased Support Tickets
The rollout may lead to an increase in support tickets as users encounter issues or confusion regarding the new settings and access controls.
- roles: Support Staff, IT Administrators
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Configutation Options**
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Opportunities**
Improved User Experience with Separate Controls
The new controls for enabling/disabling Outlook for Windows and Outlook for the web will allow organizations to tailor user experiences more effectively. This means that users can be given access to the new Outlook for Windows while restricting access to the web version, leading to a more streamlined experience based on user needs.
- next-steps: Review current configurations and determine which user groups would benefit from this separation. Communicate with users about the upcoming changes and gather feedback on their preferences for Outlook access.
- roles: IT Administrators, End Users, Product Managers
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Enhanced Documentation and Configuration Review
Organizations are encouraged to update their documentation and review configurations due to the changes in CASMailbox parameters. This presents an opportunity to enhance IT documentation practices and ensure that all configurations are up-to-date, which can improve overall IT operations and reduce future issues.
- next-steps: Assign a team to audit current documentation and configurations related to Outlook access. Develop a plan to regularly review and update documentation as part of IT operations.
- roles: IT Administrators, Compliance Officers, Documentation Specialists
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Streamlined Policy Management
The separation of CASMailbox parameters allows for more precise policy management. This can lead to better compliance with organizational policies and reduce the administrative burden of managing access controls for multiple applications.
- next-steps: Develop a policy management strategy that leverages the new CASMailbox parameters to enforce organizational standards effectively. Train IT staff on the new policies and ensure they understand the implications of the changes.
- roles: IT Administrators, Security Officers, Policy Managers
- references: https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access, https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook
Potentional Risks**
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IT Security**
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explanation for non-techies**
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change history
Date | Property | old | new |
2025-01-30 | MC Last Updated | 11/06/2024 00:18:12 | 2025-01-29T21:20:17Z |
2025-01-30 | MC Messages | Updated November 5, 2024: We have updated the content. Thank you for your patience.
We are changing how you enable or disable the new Microsoft Outlook for Windows and Microsoft Outlook for the web. [When this will happen:] General Availability (Worldwide, GCC): We will begin rolling out late January 2025 and expect to complete by mid-February 2025. | Updated January 29, 2025: We have updated the rollout timeline below. Thank you for your patience.
We are changing how you enable or disable the new Microsoft Outlook for Windows and Microsoft Outlook for the web. [When this will happen:] General Availability (Worldwide, GCC): We will begin rolling out late February 2025 (previously late January) and expect to complete by mid-March 2025 (previously mid-February). |
2025-01-30 | MC End Time | 04/18/2025 09:00:00 | 2025-04-28T09:00:00Z |
2024-11-06 | MC prepare | This rollout will happen automatically by the specified date with no admin action required before the rollout. Review your current configuration to determine 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 OneWinNativeOutlookEnabled policy state for each mailbox. The default value is Enabled. Learn more Enable or disable Outlook on the web access to mailboxes in Exchange Server | Microsoft Learn (will be updated before rollout) Enable or disable access to the new Outlook for Windows | Microsoft Learn (will be updated before rollout) #newoutlookforwindows https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook | This rollout will happen automatically by the specified date with no admin action required before the rollout. Review your current configuration to determine 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 Enabled. Learn more Enable or disable Outlook on the web access to mailboxes in Exchange Server | Microsoft Learn (will be updated before rollout) Enable or disable access to the new Outlook for Windows | Microsoft Learn (will be updated before rollout) #newoutlookforwindows https://learn.microsoft.com/exchange/clients/outlook-on-the-web/mailbox-access https://learn.microsoft.com/exchange/clients-and-mobile-in-exchange-online/outlook-on-the-web/enable-disable-employee-access-new-outlook |
2024-11-06 | MC MessageTagNames | User impact, Admin impact | Updated message, User impact, Admin impact |
2024-11-06 | MC Summary | Microsoft is updating the process to enable/disable Outlook for Windows and Outlook for the web, with changes rolling out from late January to mid-February 2025. The OWAEnabled parameter will only affect Outlook for the web, while the OneWinNativeOutlookEnabled policy will manage new Outlook for Windows. No admin action is required before the rollout. | Microsoft is updating the process to enable/disable new Outlook for Windows and Outlook for the web, starting late January 2025. The rollout will change the CASMailbox parameters, separating the controls for web and Windows versions. Organizations should review configurations and update documentation accordingly. No admin action is required before the rollout. |
2024-11-06 | MC Last Updated | 11/01/2024 00:03:57 | 2024-11-06T00:18:12Z |
2024-11-06 | MC Messages | We are changing how you enable or disable the new Microsoft Outlook for Windows and Microsoft Outlook for the web.
[When this will happen:] General Availability (Worldwide, GCC): We will begin rolling out late January 2025 and expect to complete by mid-February 2025. | Updated November 5, 2024: We have updated the content. Thank you for your patience.
We are changing how you enable or disable the new Microsoft Outlook for Windows and Microsoft Outlook for the web. [When this will happen:] General Availability (Worldwide, GCC): We will begin rolling out late January 2025 and expect to complete by mid-February 2025. |
2024-11-06 | MC Title | Microsoft new Outlook for Windows and Outlook for the web: Changing how to disable/enable | (Updated) Microsoft new Outlook for Windows and Outlook for the web: Changing how to disable/enable |
2024-11-06 | MC How Affect | We're changing the OWAEnabled parameter that enables or disables access to user mailboxes using Outlook for the web (formerly known as Outlook Web App or OWA) to block only Outlook for the web and to not affect the behavior of new Outlook for Windows.
You can manage new Outlook for Windows with the 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 is checked to see if new Outlook for Windows is allowed to run on that computer. Before this rollout, both OWAEnabled and OneWinNativeOutlookEnabled policies are checked. After this rollout, we will remove the check for OWAEnabled so you can have the chance to enable new Outlook and still disable Outlook for the web if desired. | We're changing the CASMailbox -OWAEnabled parameter that enables or disables access to user mailboxes using Outlook for the web (formerly known as Outlook Web App or OWA) to block only Outlook for the web and to not affect the behavior of new Outlook for Windows.
You 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 is checked to see if new Outlook for Windows is allowed to run on that computer. 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 if desired. |
Last updated 1 week ago