Title: Some users’ email with attachments sent from Outlook for Mac may be delivered without attachments
User impact: Users’ email with attachments sent from Outlook for Mac may be delivered without attachments.
More info: Users can verify if they’ve encountered this problem in Outlook for Mac by reviewing their Sent Items to validate if a sent message contains an attachment. If users don’t see the attachment, they can reply to the message in their Sent Items folder to reattach and send the message again.
Current status: In our review of the local reproduction data, we’ve identified a supplemental code update to optimize the number of calls for adding and removing attachments performed by the Outlook for Mac client, as well as adding more logs, which is undergoing deployment into our internal test environment. This will help reduce the frequency of redundant calls made by the client that will also aid us in our testing and review of available data for the development of a more holistic solution.
Scope of impact: This issue is specific to a very small percentage of users’ email with attachments sent from Outlook for Mac.
Start time: Monday, July 10, 2023, at 8:08 PM UTC
Root cause: A conflict occurring with how our service detects attachment IDs before sending email in Outlook for Mac is resulting in the service removing attachments on sending email.
Next update by: Tuesday, September 12, 2023, at 2:00 AM UTC
