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 – ONGOING

12/07/2023 08:47:00 AM (GMT)

NHSmail Reference : INC36943222

Microsoft Reference : EX637339

Issue Status : ONGOING

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

Current Update : 28/09/2023 08:30:00 AM – Microsoft have determined that the immediate fix to update attachment logic to reduce instances of this issue from occurring needs to be deployed incrementally at a monitored pace to ensure it successfully remediates impact without adversely impacting other aspects of the service. They’ve initiated the deployment and anticipate it will reach the affected users by mid-October 2023. They’ll aim to provide a precise completion date once one becomes available. Furthermore, the immediate fix will reduce the probability of the issue consistently occurring, though a secondary long-term fix will need to be developed in order to fully resolve the underlining issue and remediate impact. They’ll continue to provide updates on the long-term fix alongside the deployment updates for the initial fix. 

Scope of impact : This issue may affect any Outlook for Mac and Outlook mobile app user.

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 update by : Wednesday October 4, 2023, at 7:00 PM UTC