Microsoft’s first Windows 11 security update of 2026 broke shutdowns and some Remote Desktop sign-ins. Microsoft has released emergency out-of-band fixes via Windows Update, including KB5077744 and KB5077797.

Microsoft confirmed that a recent Windows update is blocking customers from accessing their Microsoft 365 Cloud PC sessions.

Microsoft’s first major Windows 11 update of 2026 quickly turned into a headache for users, after widespread reports emerged of systems failing to shut down properly and remote sign-in tools suddenly becoming unusable.

Microsoft 365 suffered a global outage affecting Teams, Outlook, and Office apps, but Microsoft confirms the issue was resolved.

Microsoft shared a temporary workaround for customers experiencing Outlook freezes after installing this month's Windows security updates.

Why is Microsoft 365 not working and which services and apps are down? Microsoft 365 faced an outage on Thursday affecting Outlook, Teams, Defender, Purview, and Store. Users reported the ‘451 4.3.2 Temporary server error’.