KB5085516: Emergency Update Fixes Microsoft Account Sign-In Broken by March Patch Tuesday
Summary: Microsoft released an emergency out-of-band update, KB5085516, on March 21, 2026, to fix a sign-in breakage introduced by the March Patch Tuesday cumulative update KB5079473. The bug caused Microsoft account sign-ins to fail across Teams, OneDrive, Edge, Excel, Word, and Microsoft 365 Copilot — even on devices with a working internet connection.
What happened: After installing KB5079473 (released March 10, 2026 as part of Patch Tuesday), affected Windows 11 devices entered a broken network connectivity state that caused any Microsoft account authentication attempt to fail with the misleading error: “You’ll need the Internet for this. It doesn’t look like you’re connected to the Internet.”
Microsoft acknowledged the bug on its Windows release health dashboard and noted that only personal Microsoft accounts were affected — organizations using Entra ID (formerly Azure Active Directory) for app authentication were not impacted.
Temporary workaround (before the fix): Microsoft advised users to restart their PCs while keeping the device connected to the internet. This would reset the broken network connectivity state. However, restarting without an active internet connection could cause the issue to reoccur.
The fix: KB5085516 is an optional out-of-band update available for Windows 11 versions 24H2 and 25H2 via Windows Update or the Microsoft Update Catalog. It includes all patches from the March 2026 Patch Tuesday rollup in addition to the sign-in fix.
Context — a busy patch week for Microsoft: This is the third emergency update Microsoft issued following March Patch Tuesday. The previous two addressed a Bluetooth device visibility issue and RRAS security vulnerabilities on hotpatch-enabled Windows 11 Enterprise devices. Microsoft also separately published guidance for C:\ drive access failures on Samsung laptops caused by a buggy Samsung Galaxy Connect app update.
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