Microsoft 365 Alert – Service Degradation – Exchange Online – Users’ email with attachments sent from Outlook for Mac and the Outlook mobile app may be delivered without attachments – RESOLVED

Announcements Habiba Tabasum

12/07/2023 08:47:00 AM

NHSmail Reference : INC36943222

Microsoft Reference : EX637339

Issue Status : RESOLVED

Issue Description : Users’ email with attachments sent from Outlook for Mac and the Outlook mobile app may be delivered without attachments.

More info : This issue affects both the Outlook for Android and iOS apps. While Microsoft are focused on remediation, users that have access to Outlook on the web can use this to bypass the problem and successfully send email with attachments

Final Update : 24/01/2024 09:08:00 AM – Microsoft’s fix deployment has completed, and the issue is resolved. Affected users may need to update their Outlook for Mac client through the Apple app store or Microsoft store to receive the fix and remediate the issue for all users.

Scope of impact : This issue is specific to a very small percentage of users’ email with attachments sent from Outlook for Mac.

Root cause : A conflict occurring with how our service detects attachment IDs before sending email in Outlook for Mac and Outlook mobile apps is resulting in the service removing attachments on sending email.

Next steps : Microsoft are continuing to investigate the conflict to understand how it was introduced and better prevent similar future impact.