Hidden contacts will reappear in Outlook
Microsoft is discontinuing the Contact Masking feature in Outlook. Previously hidden recipients will reappear in suggestions starting April 2026.
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Microsoft is discontinuing the "Contact Masking" feature in Outlook. Previously, users could hide suggested recipients in the To, Cc, and Bcc fields by clicking the X next to a name. After March 31, 2026, this will end – all previously hidden contacts will reappear in address suggestions, People suggestions, and search.
As Microsoft explains in a notice in the Message Center (MC1234566), the feature regularly caused confusion and frustration for IT support. The problem: If a user hides a recipient, it only affects their own view – other users in the same tenant will still see the contact. Furthermore, hiding has unexpected effects beyond Outlook: the individuals also disappear from suggestions in MS Teams and M365 search, even though Contact Masking was not a suite-wide contact setting.
All Outlook versions are affected – desktop, web, and mobile. Microsoft does not explicitly mention classic Outlook in the announcement. Hiding will still work as usual until the deadline, but from April onwards, all previously hidden contacts will automatically reappear. Microsoft emphasizes that the change will not affect the AutoComplete list in Outlook. Users can continue to delete entries from the completion based on past emails independently. Contacts themselves are neither added, deleted, nor changed.
Microsoft is not announcing a successor feature for managing recipient suggestions. Administrators do not need to take any active measures.
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Alternatives for Admins
For companies that need to keep recipients out of address lists, server-side admin tools are still available. Address Book Policies (ABP) in Exchange Online allow for segmented views of the global address list and are particularly suitable for multi-company tenants. Individual recipients can be hidden from address lists using the HiddenFromAddressListsEnabled attribute.
Those who want to enforce communication restrictions between specific user groups can use Information Barriers in Microsoft Purview. This feature blocks or allows communication between defined segments, but requires an M365 E5 license or a corresponding Purview add-on.
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