Microsoft Outlook to block MSIX attachments starting November
Microsoft Outlook to block MSIX attachments starting November 2026.
Intelligence analysis by Qwen 2.5 (3B)

Microsoft is blocking MSIX attachments in Outlook starting November, as part of efforts to enhance security and prevent attacks.
Microsoft is stopping people from sending certain types of files in Outlook starting next month to keep your computer safe.
Analysis
{"heading":"Enhancing Security in Outlook","subheading":"Blocking MSIX Attachments","paragraph_1":"Microsoft has announced that it will block MSIX attachments in Outlook starting November 2026. MSIX files are modern Windows installation packages tailored for specific computer architectures or configurations.","paragraph_2":"The change will begin rolling out to Exchange Online users in early November, when the new file types will be added to the BlockedFileTypes list in all OWA Mailbox policies.","paragraph_3":"This move is part of a broader effort to disable and remove Office and Windows features that attackers have abused in recent years, including attacks targeting Microsoft customers."}
Key points
- Microsoft Outlook will block MSIX attachments starting November 2026
- The change will affect Exchange Online users in early November
- This is part of Microsoft's efforts to enhance security and prevent attacks
This update will help keep your computer safe from bad guys who try to trick you with unsafe files.
Some people might not be able to send or receive certain types of files in Outlook, which could cause some inconvenience.



