Edge 156 update breaks attachment opening in New Outlook

An Edge 156 update unintentionally enabled an unnecessary configuration that prevents some New Outlook users from opening email attachments. Microsoft confirmed the issue in advisory EX1528992 and began rolling out a fix expected to take about 12 hours; saving attachments via "Save As" works as a workaround.

• Edge 156 enabled an unnecessary setting that blocks attachment opening
• The "Open" option disappears after the error; "Save As" works
• Fix rollout takes about 12 hours and requires restarting Outlook
• Outlook Classic is not affected by the issue