Outage in Microsoft 365

Some users may be unable to access their Exchange Online email using Outlook for Mac

Resolved Minor
October 21, 2025 - Started about 13 hours ago - Lasted about 7 hours

Incident Report

Title: Some users may be unable to access their Exchange Online email using Outlook for Mac User impact: Users may be unable to access their Exchange Online email using Outlook for Mac. Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
Components affected
Exchange Online

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Latest Updates ( sorted recent to last )
about 8 hours ago - at 10/21/2025 08:58PM

Title: Some users may be unable to access their Exchange Online email using Outlook for Mac

User impact: Users may be unable to access their Exchange Online email using Outlook for Mac.

More info: Some users’ Mac devices may be quarantined, which is prohibiting impacted users from accessing their email in Outlook for Mac.

Impact is specific to the latest build, 16.102.1018.1.

Current status: We've reverted the latest build of the Outlook for Mac client to the previous update version, and we’re working with users that reported the problem to test and verify that this rollback mitigates impact as expected.

Scope of impact: This issue impacts users on the latest version (16.102.1018.1) of the Outlook for Mac client.

Start time: Monday, October 20, 2025, at 4:00 PM UTC

Root cause: The latest build release contains a code issue which is causing the Exchange ActiveSync policy to block the Outlook for Mac client, resulting in the impact.

Next update by: Wednesday, October 22, 2025, at 12:30 AM UTC

about 11 hours ago - at 10/21/2025 05:39PM

Title: Some users may be unable to access their Exchange Online email using Outlook for Mac

User impact: Users may be unable to access their Exchange Online email using Outlook for Mac.

More info: Some users’ Mac devices may be quarantined, which is prohibiting impacted users from accessing their email in Outlook for Mac.

Impact is specific to the latest build, 16.102.1018.1.

Current status: We've confirmed the latest build version contains a code issue which is causing the Exchange ActiveSync policy to block the Outlook for Mac client, resulting in the impact. We're reverting the latest build to resolve the issue.

Scope of impact: This issue impacts users on the latest version (16.102.1018.1) of the Outlook for Mac client.

Start time: Monday, October 20, 2025, at 4:00 PM UTC

Root cause: The latest build release contains a code issue which is causing the Exchange ActiveSync policy to block the Outlook for Mac client, resulting in the impact.

Next update by: Tuesday, October 21, 2025, at 10:30 PM UTC

about 12 hours ago - at 10/21/2025 04:39PM

Title: Some users may be unable to access their Exchange Online email using Outlook for Mac

User impact: Users may be unable to access their Exchange Online email using Outlook for Mac.

More info: Some users’ Mac devices may be quarantined, which is prohibiting impacted users from accessing their email in Outlook for Mac.

Impact is specific to the latest build, 16.102.1018.1.

Current status: We're reviewing some affected user profiles and Outlook logs to determine our next troubleshooting steps.

Scope of impact: This issue impacts users on the latest version (16.102.1018.1) of the Outlook for Mac client.

Next update by: Tuesday, October 21, 2025, at 7:00 PM UTC

about 13 hours ago - at 10/21/2025 04:04PM

Title: Some users may be unable to access their Exchange Online email using Outlook for Mac

User impact: Users may be unable to access their Exchange Online email using Outlook for Mac.

Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.

source IsDown Microsoft Power Automate outage issues Reports started about 3 hours before official outage was reported

Users report missing flows, connection issues, error messages when accessing cloud flows, delayed or stuck automations, and failure notifications for process tasks.

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