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: Our deployment is ongoing, although it hasn’t completed at this time as expected. Currently, approximately 50 percent of previously affected users have received the fix, and we’re seeing error rates decrease as deployment continues. We’re monitoring the fix deployment and anticipate it will complete by our next scheduled update on Tuesday, January 23, 2024.
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, January 23, 2024, at 9:00 PM UTC
