MC1187400 – Syncing HiddenFromAddressListEnabled attribute across tenants for consistent Global Address List (GAL) visibility (archived)

Product:

Exchange, Microsoft 365 Apps

Platform:

Online, US Instances, World tenant

Status:

Change type:

Feature update, Admin impact

Links:

Details:

Summary:
The HideFromAddressListEnabled attribute will now sync across tenants via Entra Cross Tenant Sync, ensuring consistent Global Address List visibility. The update rolls out late November to mid-December 2025 automatically, requiring no admin action and not affecting mail flow or sign-in.

Details:
[Introduction]
We are improving People Search in the Global Address List to correctly handle the HideFromAddressListEnabled attribute. Previously, when users were synced across tenants via Entra Cross Tenant Sync, this attribute did not propagate, causing hidden users in the source tenant to appear in the target tenant's Global Address List (GAL).
With this update, the attribute will sync across Exchange and Entra directories, and a backfill process will ensure previously synced users reflect the correct visibility. Dual write ensures all future sync operations propagate HideFromAddressListEnabled correctly
[When this will happen:]
General Availability (Worldwide, GCC, GCCH, and DoD): We will begin rolling out late November 2025 and expect to complete by mid-December 2025.
The update will run automatically in the background and may take several weeks to complete, depending on tenant size.

Change Category:
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Scope:
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Release Phase:

Created:
2025-11-18

updated:
2025-11-18

Task Type

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summary for non-techies**

The update rolling out between late November and mid-December 2025 will ensure that the HideFromAddressListEnabled attribute in Microsoft 365 syncs correctly across all tenants, automatically respecting users' preferences to remain hidden from the Global Address List without requiring any action from administrators.

Direct effects for Operations**

Inconsistent Global Address List Visibility
Users hidden in the source tenant may appear in the target tenant's Global Address List (GAL) if the change is not prepared for, leading to potential privacy concerns and confusion among users.
   - roles: Tenant Admins, End Users
   - references: https://techcommunity.microsoft.com/t5/exchange-team-blog/announcing-the-hiding-of-users-in-the-global-address-list-gal/ba-p/123456

Impact on Custom Scripts and Workflows
Existing custom scripts or workflows that rely on GAL visibility may fail or produce incorrect results if not reviewed and updated post-change, leading to operational disruptions.
   - roles: IT Administrators, Developers
   - references: https://docs.microsoft.com/en-us/powershell/exchange/exchange-online-powershell?view=exchange-ps

Helpdesk Communication Challenges
Helpdesk teams may face increased inquiries and confusion from users regarding visibility changes in the GAL, impacting their ability to provide timely support.
   - roles: Helpdesk Staff, End Users
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2021/06/15/understanding-the-global-address-list-in-exchange-online/

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Potentional Risks**

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Data Protection**

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IT Security**

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explanation for non-techies**

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