User impact: Users may see unwanted add-ins appearing automatically across all Outlook clients.

More info: These add-ins are configured to be available to users by admins but aren’t expected to be automatically installed. To bypass this issue, affected users can run the “Set-App -Identity -OrganizationApp -PrivateCatalog -DefaultStateForUser Disabled” command to remove add-ins that are unintentionally appearing.

Current status: We’ve verified with a subset of affected users that performing the identified workaround successfully mitigates the impact. We’re preparing a permanent fix for deployment, which we expect will take several weeks to saturate. We’ll provide a resolution timeline once available.

Scope of impact: Impact may occur for some users that may see unwanted add-ins appearing automatically across all Outlook clients. This section may be updated as the investigation progresses.

Start time: Friday, July 17, 2026, at 10:26 AM UTC

Root cause: A portion of the Exchange Online add-in sync pipeline isn’t processing add-in state information as expected. This is causing incorrect EnabledStatus values being returned and Outlook automatically displaying add-ins configured as Available, which is resulting in impact.

Next update by: Friday, September 11, 2026, at 6:30 PM UTC