Users’ .zip files attached to S/MIME encrypted messages may not be displayed in Outlook on the web

Title: Users’ .zip files attached to S/MIME encrypted messages may not be displayed in Outlook on the web

User impact: Users’ .zip files attached to S/MIME encrypted messages may not be displayed in Outlook on the web.

More info: Users may be able to bypass impact by clicking the “Reply to All,” “Reply,” or “Forward” button on the mail item that has the issue to launch the compose message screen. After that, save the message as a draft and check the draft item to see the attachment. As an alternative method, users can use the Outlook desktop client without error.

Current status: We’re continuing our investigation of the provided HAR logs to confirm that the previously mentioned recent change is responsible for impact, after which we’ll initiate development of a fix to repair this issue.

Scope of impact: Users serviced by the affected infrastructure who received attached .zip files to Secure/Multipurpose internet Mail Extensions (S/MIME) encrypted messages may be unable to view them when using Outlook on the web.

Next update by: Tuesday, March 19, 2024, at 7:00 PM UTC